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Cloud Computing
Dan Sullivan
The Definitive Guide to Cloud Computing
Dan Sullivan
Introduction to Realtime Publishers
by Don Jones, Series Editor
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The Definitive Guide to Cloud Computing
Dan Sullivan
Introduction to Realtime Publishers ................................................................................................................. i Chapter 1: Changing the Way We Deliver Services with Cloud Computing .................................... 1 Overview ................................................................................................................................................................. 1 The Moving Target that Is Cloud Computing ...................................................................................... 3 A Brief Introduction to Cloud Computing ................................................................................................. 4 A Massively Scalable Infrastructure ....................................................................................................... 5 Rapid Allocation of Virtual Servers .................................................................................................... 6 Standard Hardware Platform ............................................................................................................... 7 Persistent Storage in the Cloud ........................................................................................................... 7 Universal Access ............................................................................................................................................. 8 . Fine‐Grained Usage Controls and Pricing ............................................................................................ 9 Standardized Resources .............................................................................................................................. 9 Management Support Services .............................................................................................................. 10 Drivers Behind Cloud Computing .............................................................................................................. 10 A Better Way to Consume Services ...................................................................................................... 11 Service‐Oriented Architecture in the Cloud ................................................................................ 11 Differentiated Levels of Service ........................................................................................................ 12 More Efficient Delivery of Services ...................................................................................................... 12 Management Infrastructure ............................................................................................................... 13 Optimization of Workloads Across Shared Infrastructure ................................................... 13 Self‐Service Management .................................................................................................................... 14 Monitoring ................................................................................................................................................. 15 Improving the User Experience through Cloud Computing ...................................................... 15 Changing Economics of IT ............................................................................................................................. 15 Reducing Capital Expenditures ............................................................................................................. 16 Efficiently Allocating Resources ............................................................................................................ 16 Rapidly Delivering IT Services ............................................................................................................... 17 ii
The Definitive Guide to Cloud Computing
Dan Sullivan
Aligning Business Strategy and IT ............................................................................................................. 18 Summary .............................................................................................................................................................. 19 Chapter 2: Demystifying Cloud Computing ................................................................................................ 20 A Note on Terminology .................................................................................................................................. 20 Searching for a Common Definition: 3 Fundamental Elements of Cloud Computing ......... 21 Massive Scalability ...................................................................................................................................... 21 Computing Resources ........................................................................................................................... 22 Storage Resources .................................................................................................................................. 24 Network Resources ................................................................................................................................ 24 Ability to Easily Allocate Cloud Resources ....................................................................................... 25 Service Management Platform ............................................................................................................... 26 Service Catalog of Standardized Services ..................................................................................... 26 Policy Definition and Enforcement ................................................................................................. 26 A Cloud by Any Other Name .................................................................................................................... 27 Different Types of Cloud Computing Services ..................................................................................... 28 Infrastructure Services .............................................................................................................................. 28 Computing on Demand ......................................................................................................................... 29 Storage on Demand ................................................................................................................................ 30 Business Intelligence Use Case ......................................................................................................... 30 Platform Services ......................................................................................................................................... 31 Relational Database Services ............................................................................................................. 31 Application Servers ................................................................................................................................ 33 Security Services ..................................................................................................................................... 33 Application Services ................................................................................................................................... 33 Messaging Queues .................................................................................................................................. 34 Distributed, Parallel Processing ....................................................................................................... 35 Applications and Business Services ..................................................................................................... 36 iii
. 51 Cost Control and Ability to Scale to Demand ....... 56 Standardization and Automation .............................................................................................................................. 38 Public Clouds ...................................................................................................................................................................................................... Managing Business Services and Workloads ........................................................................................................................................................................................................................................................................................................................... 53 Lowering Operational Costs with Cloud Computing .. 42 New Services Under a Traditional IT Service Model ........................................................................................................................................................................................ 53 Lowering Capital Costs with Cloud Computing ...................................... 44 Scenario 2: Advanced Analytics for Auto Insurance Premium Calculations .................................................................................................................................................................................................... 44 Scenario 1: Tutorial Videos for the DIY Customer .............................................................. 58 Service Management Reporting ............................................................................................................................................................................... 49 Scenario 2: Advanced Analytics in the Cloud .................................... 39 Summary .............. 39 Hybrid Clouds ............................................................. 59 iv ............................................................................................. 49 ................... 40 Chapter 3: Enabling Business Innovation by Using Cloud Computing .............................. 46 New Services Under the Cloud Computing Model .................... 54 On‐Demand Provisioning ....................................................................................................... 41 Launching a New Business Service ...............The Definitive Guide to Cloud Computing Dan Sullivan Consolidating Enterprise Applications ............................................................. 38 Cloud Delivery Models ................................................................................................................................................................................. 53 Source of ROI in the Cloud ...................................................................................................................................................................................................... Advantages of Doing Business with Cloud Computing ................................................................. 49 Scenario 1: Tutorial Videos in the Cloud ........................... 50 Time to Deploy Services ................................... 55 Reducing Marginal Costs of Systems Administration ............................................. 36 .......................................................... 52 Adaptability of Resources ................................................................................... 37 Common Attributes of Cloud Service Models ................. 39 Private Clouds ...............................................................................................
..... 63 Business and Technology Alignments: The Ideal vs.......................................... Measuring the Value of a Cloud ............................................................................................................................................................................................................................................................................................................................................................................................................................................. 60 Chapter 4: How Cloud Computing Will Help Your Business ............................................................................................................................................... 65 Identify Operational Inefficiencies ................ 76 Introducing Private Cloud Consumption Model ........................................................... 63 Identify Business Priorities .............................. 80 Infrastructure Maintenance ........................................................................... 73 Governance Capabilities ......................................................................................................................................................................................... 78 Managing a Private Cloud ................................ 62 How Cloud Computing Can Help Your Business ................................. 77 Enabling Application Services in the a Cloud ..................................................................................................... 59 Summary .............................................................................................................................................................. 70 Application Capabilities .................... 74 Management and Reporting Capabilities ...................................................................................................................................................... 76 Deploying Existing Infrastructure in a Private Cloud ...................................................................................... 69 Platform Capabilities ............................................................................................................... 68 Infrastructure Capabilities ................................ 80 Changes to Capital Cost ........................................... 70 Application Stacks ................................................................ Reality ............................................................................... 76 Introducing Public Cloud Consumption Model ................................................................................................................................................................................................................................ 81 v ........ 75 Introducing a New Model for Consumption and Delivery ............................................... 69 OS Consolidation .......................... 66 Identify Barriers to Innovation ........................................................................................................ 67 Assessing Current Capabilities ......................................................................................The Definitive Guide to Cloud Computing Dan Sullivan Assessing the Business Value of Cloud Services ........ 80 Labor Costs ....................... 80 Changes to Operational Cost ............................................................................................................................................................................................................................. 78 ...........................................................................................................................................................................
................................................................................................................................................................................. 94 Designing for Manageability ................................................................................................................................................................................................................................................ 98 Deploying Layered Technical Services ....... 81 Summary ........................................................................................................................................................................................................................................................................................................................................................................................................ 99 Business Services in the Cloud: Use Case Scenarios ..................................................................................... 102 vi .................................................. 92 ......................................................................................................................................................................................................... 85 Existing Applications Infrastructure: The Current State of Affairs ........... 85 Additional Requirements for New Applications .......... 88 Aligning Requirements to Cloud Services ............................................................................................................................................................................................................................................................................................................. 87 Assessing Workloads ................................................ 100 Business Intelligence Use Case ............. 97 Managing Cloud Provisioning ........................... 97 Monitoring Jobs in the Cloud .......................................................................................................................................................................................... 83 Prioritizing According to Business Drivers .............................................................................................................................The Definitive Guide to Cloud Computing Dan Sullivan Facilities Operations ............ 89 Designing for Scalability ......... 101 Mixing Workloads ............................................................................... 84 Defining Requirements ........................................................................................................................................................................................................ 87 Scheduling ............................................. 82 Chapter 5: Strategies for Moving to the Cloud ........................................................ 100 New Customer Initiative Use Case ............... 92 Providing Scalable Computing Resources .......................................................................................................................... 83 Planning Principles for Moving to Cloud Computing ................................................ 99 Delivering Business Services ................................................................................................... Using Cloud Services in Scalable Ways ................................................... 89 Architectural Principles for Cloud Services ........................................................................................ 88 Cost Recovery .............................................................................. 87 Capacity Planning ............................................ 81 Simplified Accounting ............................................
........................................................................................................................................................................................ 119 ...................................................... 113 Storage Virtualization ........................................................................................ 112 Providing Storage Services .................................................................... 109 ...................................................................................................................................... 116 Network Services for Cloud Computing ............................................................................... Virtualization of Resources .............................................................................................................................. 106 Hardware Independence ................................................ 117 Redundancy in the Network ................................................................................................................................................................................................................................................................................................................................................................................................................. 116 Intra‐Cloud Replication ....................................................................................................................................................................................... 116 Capacity ........................................................................................................................... 119 vii ............................................................................................................................... 107 Services Layer ............................................................................................................................................ 108 Service Management Processes ................................................... 119 Image Management .................. 110 Implementing Virtualization ......................................... 118 Cloud Operations ............................................................... 113 Backups and Cloud Storage ........................................ 107 Standardized Service Pricing ................................. 117 Loading Data into the Cloud .The Definitive Guide to Cloud Computing Dan Sullivan Summary ......................................................................................................................................................................................................... 111 Failover and Redundancy ....................................................................................................................................... 104 .............................................. 106 Logical Units of Computing Resources ............................................................................................................................................................................................. 115 Management Reporting for Storage Virtualization ............................................. Levels of Cloud Architecture ....................................................................................................................................................... Providing Compute Services ..................................................................................................... 105 .......................................... Workload Management ................... 103 Chapter 6: Identifying the Right Cloud Architecture for Your Business ..................................................... 117 Management Reporting ........................................................................................ 110 Hardware Selection ..................................... 111 Management Reporting .............
.......... 124 Assessing Readiness for Cloud Computing .................................................................................................................................................................................. 122 Service Management Layer ...................................................................................................................................... 131 Customization and Specialized Requirements ..... 125 Coupling of Components ......................................... 121 Managing Workload ...................................................................... 127 Platform Independence ....................... Preparing to Manage Cloud Services................................................................................... 126 Ability to Execute Multiple Instances .............................. 125 Levels of Centralization ....................................................................................................................................................... 135 Labor Value ....................... 127 Self‐Management of Compute and Storage Resources ....................................................................................... 126 .......................... 129 Standard Platforms and Application Stacks ................................. 124 .................................... 122 Maintaining Security ......................................................................................... Web Application Architecture ......... 133 Value Metrics .................................................................................................................................................................................................................................................................. 122 Summary ..................................................................................................................... 132 Aligning Business Strategy with Cloud Computing Services ..................................................................................................................................................................................................... 130 Determining Required Platforms and Application Stacks ....................................... 130 Required Support Services ............................................................................................... and Hybrid Cloud Services ........................................................................ 122 Performing Maintenance and Upgrades ........................................................................................................... 136 viii ................................................................................................................................................................ 133 Workload Analysis ........................................................................................................................................................... 135 .......................The Definitive Guide to Cloud Computing Dan Sullivan Services Layer: Adapting IT Operations to Cloud Infrastructure ......... Public.................................................................................................................................................................... 134 Hardware and Software Values ........................................ Accessibility of Components ........................................... 121 Designing for Recoverability ............................................................................... 136 Role of Private.................................................................................................... 123 Chapter 7: Roadmap to Cloud Computing: The Planning Phase ..........................
....... 145 Establishing a Private Cloud .........................................................................................................................................................The Definitive Guide to Cloud Computing Dan Sullivan Planning for Growth ............ 143 Summary ........ 146 Servers and Network Equipment ........................................................................................................................................................................................................... 139 Standardizing to Reduce Complexity ................................................................................... 140 Virtualizing Physical Resources ....... 146 Environmental Issues .............................................................................................................................................................................................................. 150 Cloud Management Services .................................... 152 Cloud Management Reporting ........................... 139 Streamline Service Management ............................................ 142 ...................................................... 141 Capacity Commitments ............................................. 142 Availability and Recovery Management .............................................................................................................. 146 Deploying Hardware for a Private Cloud ........................................................................................................ 147 Redundancy and Avoiding Single Points of Failure ................ Storage Infrastructure .......................................................................... 139 Planning for Centralizing Resources ................................................................................................................................................................................................................................................................................................. 149 Providing Application Stacks .................................................................................................................................................................................. 153 Migrating Compute and Storage Services to a Private Cloud ................................................................................................................................................................................. 137 Long‐Term Management Issues ............................................................ 150 Cloud Management Policies ...................................... 154 ........................................................................................................... 147 Deploying Network Services for a Private Cloud ....................................................................................................................................................................................... 154 Prioritizing Based on Business Drivers ......................................................................................................................................................................................... 154 ix ..................................... 144 Chapter 8: Roadmap to Cloud Computing: The Implementation Phase .......................................................................................................................................... 142 Network Infrastructure ...................... 141 Committing to SLAs ..................................................................................................................................... 143 Compliance Requirements and Cloud Services ........................................ Business Driver #1: Cost ....
.. 163 Usage Tracking and Accounting Services ..................................................................................................................................................................................................................................................................................................................................................... 172 Pricing Cloud Services ............................................................................ 163 Service Validation and Release Management ................................................................................................................................ 158 Migrating Data to Cloud Storage ................................................................................................... 173 x .............................................................................. 170 Availability and SLAs ........................................................................................................................... Integrating Service Management with the Cloud ..... 162 Service Level Management .................. 161 Service Catalog Management ... 157 Deploying Management Applications ............................................................................................................................................................................................................................................................................................................... 157 Migrating End User Applications .. 168 Protecting the Integrity of Business Services ................................................................................................... 163 Capacity Planning .................................................... 164 Summary ........................................................................................................................................................................ 159 Managing Cloud Services ...................The Definitive Guide to Cloud Computing Dan Sullivan Business Driver #2: Computing Resources ........................... 172 ................................................................................................................................................ 161 ...................................................................................................................................... 155 Reallocating Servers ..................... Growth....................... 165 Chapter 9: Maintaining a Cloud Environment: Governance............. Controlling Access to Cloud Services ............................................................................................................................................ 156 Testing and Quality Control ...................................................................... 164 Extending a Private Cloud with Public Services ................................................................................................ 170 Confidentiality in the Cloud ................ 158 Building Virtual Machine Images ................................... 166 Governance Issues in the Cloud Computing .......................................................................................................... 158 Post‐Implementation Checklist ............................................................................................................................................................................................................ 162 Availability Management .............. 158 Migrating Access Privileges to the Cloud... 156 Deploying Cloud‐Enabling Applications .............................................................. and Security .........................................................................................
........... 182 Entitlements and Access Controls .................................................................................................................................. 174 Key Resources in Cloud Computing ....................................................................................................................The Definitive Guide to Cloud Computing Dan Sullivan Cost Allocation ....................... 173 Competitive Pricing .............................................................................................................................................................................................................................................................................................. 176 Baseline Measures ................... 176 Growth Projections ......................................................................................... 174 Planning for Growth ............ 180 Physical Distribution of Data Centers ...................................................................................................................................... 185 Aligning Business Drivers with Cloud Services ............................. 175 Baseline and Initial Growth Projections ................................................................................................. 187 Understanding Business Objectives .......................................................................................................................................................... 190 Identifying Weaknesses in Existing IT Service Delivery ..................................... 177 Expanding Using a Public Cloud ........................ 179 Mitigating Risks Through Architecture ................................................................................... 193 Planning for Transition to Cloud Computing ........................................... Prioritizing Initiatives ....................... 181 Security in the Cloud ................................................................................................................................................................................................................ 184 Chapter 10: Key Steps in Establishing Enterprise Cloud Computing Services ............................ 190 Improving Existing Processes ........................................................................................................................................................................................................................................................................................ 192 ...... 194 xi ................................... 183 Vulnerability Assessment and Patching .............................................................................. 187 Cloud Computing Enables Innovation ........................................................................................................ 183 Summary .... 180 Redundant Infrastructure ............................................................................. 193 Assessing the Current State of Readiness ...................................................................................................................................................................................................................................................................................................................................................................................................................... 188 Accommodating Varying Demand for Services .................................................................... 182 Identity Management in the Cloud ...........................................
................................................................................................................................................................................................................... 202 Operational Issues .................................................................................... 197 Implementing a Cloud Infrastructure ............................................ 202 Business Management Issues ..The Definitive Guide to Cloud Computing Dan Sullivan Indentifying the Differences Between Current Infrastructure and the Infrastructure to Deploy for the Cloud ................... 204 xii .......................................................................................................................................................... 195 Determining the Best Cloud Model for Your Requirements ................................................................................................................................ 201 Managing and Maintaining a Cloud ...................................................................................................................... 203 Summary ................................................................................................................................................................................................................. 200 Using a Hybrid Private‐Public Cloud ............................................................... 196 Planning for Long‐Term Management and Stability .................................... 198 Adapting Public Cloud Services ............................................................. 198 Implementing a Private Cloud ........................................
reproduced. images. audio. please contact us via e-mail at info@realtimepublishers. uploaded.com.The Definitive Guide to Cloud Computing Dan Sullivan Copyright Statement © 2010 Realtime Publishers. THE IMPLIED WARRANTIES OF MERCHANTABILITY. except that one copy may be downloaded for your personal. TITLE AND NON-INFRINGEMENT. exemplary or consequential damages whatsoever resulting from the use of any information contained in the Materials. and/or video) may not be copied. FITNESS FOR A PARTICULAR PURPOSE. The Materials may contain trademarks. In no event shall Realtime Publishers or its web site sponsors be held liable for technical or editorial errors or omissions contained in the Materials. The Materials are subject to change without notice and do not represent a commitment on the part of Realtime Publishers or its web site sponsors. You are not permitted to use these trademarks. This site contains materials that have been created. republished. In connection with such use. developed. transmitted. services marks and logos that are the property of third parties. including without limitation. If you have any questions about these terms. and published with the permission of. xiii . or commissioned by. noncommercial use on a single computer. EITHER EXPRESS OR IMPLIED. Realtime Publishers (the "Materials") and this site and any such Materials are protected by international copyright and trademark laws. All rights reserved. in whole or in part. The Materials (including but not limited to the text. Realtime Publishers and the Realtime Publishers logo are registered in the US Patent & Trademark Office. special. for any direct. or distributed in any way. All other product or service names are the property of their respective owners. you may not modify or obscure any copyright or other proprietary notice. services marks or logos without prior written consent of such third parties. or if you would like information about licensing materials from Realtime Publishers. THE MATERIALS ARE PROVIDED "AS IS" WITHOUT WARRANTY OF ANY KIND. INCLUDING BUT NOT LIMITED TO. incidental. posted. indirect.
The Definitive Guide to Cloud Computing describes the technical. The chapter concludes with a discussion on aligning business strategy with IT services. software. This guide examines the essential technical and business aspects of cloud computing in order to provide a broad assessment of the benefits and challenges facing adopters of cloud computing. creating new hardware technologies. operational. The advent of cloud computing is one of those events. it is much more. Overview Cloud computing is a broad‐ranging and still‐developing set of technologies and business practices. and most recently mobile devices. Cloud computing offers new ways to provide services while significantly altering the cost structure underlying those services. and optimizing business processes.] Chapter 1: Changing the Way We Deliver Services with Cloud Computing Computing is constantly changing. Business processes changed and computing expanded beyond the reach of large volume highly‐focused back office systems supporting core operations to widely adopted collaboration and personal productivity applications. introduces cloud computing and its impact on how we deliver services. 1 .The Definitive Guide to Cloud Computing Dan Sullivan [Editor's Note: This eBook was downloaded from Realtime Nexus—The Digital Library for IT Professionals.com. Software development followed a similar trajectory with an evolution that started with batch‐oriented mainframe applications and moved through client server models to highly distributed service‐oriented architectures and Web applications. especially with regard to cloud computing. this chapter. Cloud computing in its simplest form is a model for allocating compute and storage resources on demand. In this chapter. we examine the business drivers behind cloud computing and the related issues of the changing economics of information technology (IT). and organizational aspects of cloud computing and provides a roadmap for navigating the emerging landscape of cloud computing. These new technical and pricing opportunities drive changes in the way businesses operate. improving software. Mainframe computing was followed by mini‐computers. and business processes converge in ways that create significant new opportunities for delivering business services. Sometimes the changes in hardware. each deals with a significant aspect of cloud computing: • Chapter 1. In practice. The history of computing is almost a constant stream of advances.realtimepublishers. This book consists of 10 chapters. which were followed by personal computers. All leading technology eBooks and guides from Realtime Publishers can be found at http://nexus.
The Definitive Guide to Cloud Computing •
Dan Sullivan
Chapter 2 identifies the essential elements of cloud computing, discusses different types of cloud computing services and different types of cloud delivery models, ranging from public to private cloud services. In Chapter 3 we examine the business advantages of cloud computing and the various sources of Return on Investment (ROI) in cloud computing. The business case for cloud computing continues in Chapter 4. Topics include identifying business priorities, assessing current capabilities, determining considerations for adopting a cloud model for service delivery and consumption, and measuring the value of a cloud. In Chapter 5 the topic shifts from the business case to understanding how to plan for a cloud and how to assess architecture options with regard to cloud computing. Use cases are included to highlight some of the practical considerations in developing a plan to move to cloud computing. Chapter 6 delves deeper into the technical issues introduced in Chapter 5. These include providing high‐availability compute, storage, and network services. Cloud management and adapting IT procedures to the cloud are also discussed. In Chapter 7, we take a process‐oriented approach and consider how to use the information developed in the previous chapters and apply it to specific business needs. Subject areas include performing workload analysis, managing cloud services, centralizing resources, and defining service level agreements (SLAs). The planning topics of Chapter 7 are followed by Chapter 8. The focus of this chapter is on establishing a private cloud, transitioning compute and storage services, and operational issues managing cloud services. Chapter 9 delves into long‐term management issues ranging from controlling access to cloud services to capacity planning and risk mitigation. The Definitive Guide to Cloud Computing concludes with Chapter 10. This chapter consolidates and summarizes the essential aspects of planning, implementing, and managing cloud computing services.
• •
• •
The Definitive Guide to Cloud Computing
Dan Sullivan
Hardware Standardization
Virtualization and other Software Advances
Enterprise Cloud Computing
IT Management and Business Practices
Figure 1.1: Enterprise cloud computing is the product of the confluence of advances in three distinct areas: server hardware standardization, virtualization and other software advances, and IT management and practices. Without all three, enterprise cloud computing would not be possible.
The Moving Target that Is Cloud Computing
Given the speed at which IT changes, writing a definitive guide can be like designing and building a plane while flying in it. This is especially true of cloud computing. Public clouds are well established and private clouds are emerging as an alternative delivery model of cloud services. Identifying which existing applications are readily ported to the cloud while spotting others that are best run on existing platforms is an ongoing process. Applications are being built that take advantage of high‐performance, distributed computing through the use of new programming paradigms and database designs. Vendors are revising their infrastructure management tools to support clouds. Cloud computing is a quickly moving target. With the relentless pace of change in cloud computing technologies and practices, one might argue that it is too early and cloud computing too volatile to suggest a roadmap for understanding and adopting cloud computing. This argument has some merit, but its validity assumes we focus on low‐level implementation details. Rather than try to define low‐level best practices in this book (it is too early for that), we base this work on the principles and practices that IT professionals have long used to adapt and adjust to changing technologies and business conditions.
The Definitive Guide to Cloud Computing
Dan Sullivan
Change is nothing new to IT, and our past experience is a sound guide to understanding cloud computing. With that in mind, recognition of the following facts will guide the approach taken in this book: • Cloud technology will continue to evolve in intelligible ways. We understand the current state of cloud technology and recognize that it is a product of earlier technologies. Changes in cloud computing come from not just from changes in underlying technologies but also from the ways we combine and use these technologies. Business processes, workflows, and cloud management will drive the way we combine cloud techniques. The fundamentals of computing principles have not changed. Basic building blocks of IT consist of computing, storage, and network resources. The underlying principles of serial and parallel computing have been known for generations. Design and management principles that have guided us in the past are still relevant. Business services drive the adoption and continued use of cloud services. Unless you are a computer scientist, cloud computing is a means to an end, not an end in itself. In technology, as in the evolution of life, those that adapt what has worked well in the past to new conditions and find ways to build on those past successes to address novel challenges are rewarded. There will be no single best model of cloud computing for all applications. The specific conditions and requirements of a service will shape the optimal use of cloud computing for that service.
Our goal in this book is not to prescribe precise regimens for implementing a specific cloud computing application. Instead, the objective is to provide the reader with a background in the underlying technologies and business practices of cloud computing along with a roadmap for moving from the theory to practice of cloud computing.
A Brief Introduction to Cloud Computing
Cloud computing is a model for delivering information services that provides flexible use of virtual servers, massive scalability, and management services. With the dictionary definition out of the way, we can now proceed to describing cloud computing in terms of its essential features and how it functions alongside other information technologies. Cloud computing is a unique combination of capabilities which include: • • • • • A massively scalable, dynamic infrastructure Universal access Fine‐grained usage controls and pricing Standardized platforms Management support services
The Definitive Guide to Cloud Computing
Dan Sullivan
These capabilities enable a number of variations in cloud computing services. For example, one service might provide "raw iron" servers for running specialized applications, another offers on‐demand relational database services, while yet another provides a fully‐featured Customer Relationship Management (CRM) application. Cross Reference Chapter 2 will examine different types of cloud computing options in more detail; for now, we will restrict the discussion to features that are common to most cloud computing options.
A Massively Scalable Infrastructure
If we had to choose one characteristic that most distinguishes cloud computing from other models, it is the massively scalable infrastructure. In theory, one has the potential for massive scalability without the cloud provided one has the financial resources to acquire and the skills to manage a massively distributed infrastructure. The cloud puts that kind of theory into practice. Massive scalability from the service consumer perspective means the end user controls allocation of compute or storage services as needed. In the past, acquiring additional compute cycles required either procuring additional hardware, which could take weeks, or fitting jobs onto existing servers. Procuring new hardware has obvious time and cost drawbacks, but running jobs on other servers is far from a panacea. It is not uncommon to run into problems such as: • • • • Incompatibilities with the operating system (OS) or applications on the server Conflicts in the scheduling of workloads Difficulties allocating costs to owners of the jobs running on the server Irresolvable violations of security policies regarding access controls and data protection policies
These problems can occur when trying to share a single server across application or organizational boundaries let alone hundreds or thousands of servers that may be required for a compute‐intensive job. The problems are avoided with cloud computing because of three characteristics of the technology: • • • Rapid allocation of virtual servers Standardized hardware Persistent cloud storage
Together, these characteristics provide the benefits of sole use servers with the efficiencies of shared resources.
Often. a user allocates the number and type of virtual machines needed to perform a task. these physical servers will support multiple virtual machines each dedicated to different tasks (see Figure 1. the distribution of jobs and number of virtual servers running on a set of physical servers can change quickly in a cloud. such as a Web server role or application server role. Regardless of which model is used. the implementation details. The virtual machines run a task as long as required and then shut down when the task is complete. it appears to the cloud users that virtual machines are no longer allocated to them. large numbers of physical servers are ready to respond to the specific requests for computing services. A slightly more complicated setup would require the user to specify a number of servers and the roles each server carriers out. As Figure 1. logically. clouds can rapidly allocate virtual machines in response to the computing needs of users.2 shows. are cloud‐specific. (Actually. Different cloud models require or support (depending on your perspective) different levels of configuration information from users.) In a cloud. such as whether a virtual machine is actually shut down or allocated to another job. Figure 1. Another model requires users to specify a specific virtual machine image to execute on each of the virtual machines requested. 6 . a user may only need to specify the number of servers she would like dedicated to her job. In a cloud.2: Virtual machines are quickly allocated and deallocated to specific tasks in the cloud. In the cloud. physical servers become shared resources without the drawbacks previously described. In a simple case.2). Anyone who has waited hours or days to have an OS and application stack installed on a server may wonder how cloud computing servers can switch among uses so quickly.The Definitive Guide to Cloud Computing Dan Sullivan Rapid Allocation of Virtual Servers Cloud computing avoids these problems by decoupling physical servers from applications and single users.
and 320 GB of local storage Advanced server: 64‐bit. With persistent cloud storage. data is stored and made accessible to any server in the cloud. but many of the computations run on these servers will generate data that must be stored for extended periods of time. a cloud service provider has control over the network architecture and resources. 8GB of memory. subject to access control restrictions. any locally stored data would be lost. but once the virtual server is deallocated. It is useful to have local storage on servers for temporary needs. the same cannot be said for network resources. 7 . Problems potentially can arise when moving data into and out of the cloud. and 1 TB of local storage In practice the cloud provider may have all 64‐bit. The combination of rapid provisioning of standard hardware and the use of persistent storage enable massive scalability. and networking. The Potential Network Bottleneck Three types of resources are fundamental to cloud computing: computation. 4 core. cloud providers are in a position to make those changes. 16GB of memory. 16GB of memory servers but will vary the number of virtual machines to accommodate the mix of services requested by users. Persistent Storage in the Cloud Rapidly allocating and deallocating virtual machines allows for efficient allocation of computing resources. This is especially the case when there is an initial. such as: • • • Basic server: 64‐bit. If additional bandwidth is required to maintain service levels. 8 core. Within a cloud infrastructure. 2 cores. Cloud providers may offer different levels of computing services by offering the functional equivalent of different physical configurations. 2GB of memory. such as the x64 architecture. large data upload from an existing non‐cloud storage system. 8 core. Decoupling persistent storage from servers is another way cloud computing provides for fine‐grained control over resources. and 320 GB of local storage Midsize server: 64‐bit. storage. By standardizing on hardware. applications and OSs can run on many combinations of servers within the cloud without incurring additional overhead required to manage many different types of servers. It can also occur if large volumes of data are generated rapidly and must be moved to the cloud.The Definitive Guide to Cloud Computing Dan Sullivan Standard Hardware Platform Another enabling characteristic of cloud computing is the use of standard hardware platforms. Technology is in place now to enable massive scalability of compute servers and storage capacity.
Figure 1.The Definitive Guide to Cloud Computing Dan Sullivan In the case of private clouds. a single company would control the cloud infrastructure and the network resources between the source of the data and the cloud. and that can vary widely. Universal access should not be confused with open access. although it was not too long ago that proprietary email systems required local network connections or virtual private network (VPN) access to use our email. Figure 1. Although businesses may have the resources to purchase additional bandwidth. these figures demonstrate the limits of large‐scale public network infrastructure in different regions. especially with regard to private clouds. access to cloud computing resources can leverage Internet protocols to ensure widespread access. Companies and governments deploying private clouds will have authentication and authorization systems in place to control access to private cloud resources.3 shows the wide variation in average national broadband speeds. This may not be a viable option for repeated use. avoiding the need to use public network infrastructure. Even public clouds require some degree of identity management in support of management reporting and billing. Similarly. we have universal email access over the Internet.3: Average national broadband speeds (Mbps) vary widely by region (Source: The Akamai State of the Internet Report 2nd Quarter 2009. Today. Public clouds depend upon public network infrastructure. Volume 2 Number 2). Universal Access Another defining characteristic of cloud computing is universal access from anywhere on the Internet. One way to mitigate the problem of the large initial data load is to physically ship storage media to the cloud provider. another option is to generate and store data in the cloud. 8 .
increasing customization of images incurs additional management costs and an associated decrease in marginal benefit. like the load on the system over the life of the server. a cloud can provide a few different configured servers. 9 . cloud providers avoid excessive management and maintenance expenses and keep the marginal costs of expanding the cloud to a minimum. There is room for a range of options in cloud computing. If we opt for excess capacity. such as Linux or Microsoft OSs and LAMP (Linux. however. Apache HTTP Server. Figure 1. we risk not meeting SLAs.The Definitive Guide to Cloud Computing Dan Sullivan Fine‐Grained Usage Controls and Pricing The economic benefits of cloud computing are one of the key drivers to adoption. we pay up front for a substantial resource with approximately a 3‐year useful lifespan and some residual value at the end of that period. We no longer have to make purchase decisions based on single server considerations. we incur unnecessary costs. virtualization. a couple of different OSs. Similarly. Standardized Resources Cloud computing provides standard hardware. This. Cloud computing can adjust the compute and storage services as application demand dictates. Trying to optimize purchase decisions at this granularity is difficult because the ROI depends on many difficult‐to‐gauge factors.4: At some point. we purchase and pay for storage based on what is actually needed now. is not homogenization. Standardization.Net Framework application stacks. One of the features that enable this benefit is fine‐grained usage controls and pricing. By limiting the range of options. such as peak capacity requirements. has to be balanced with business requirements that may justify a greater range of customization. we provision additional resources from the cloud and release them when the demand is met and pay only for what is used. however. Cloud computing models allow us to purchase compute resources based on the mixture of jobs that need to be done now. If we undersize a server. During period of peak demand. and several different application stacks to choose from. which will vary with changing business conditions and requirements. MySQL database and Perl/Python programming languages) or Microsoft . For example. and application platforms. When we purchase servers.
Drivers Behind Cloud Computing Cloud computing changes the way we consume and provide services and in the process improves the user experience. and the role of management support services. They include: • • • • Provision servers Search and select virtual images to run on server instances Allocate persistent storage Monitor jobs executing on allocated servers Management reports are especially important for managing costs. 10 . Storage reports and network bandwidth use reports might help identify jobs that involve transferring data into and out of the cloud at a cost greater than using persistent storage services to store that data in the cloud. These include reporting on: • • • • Time periods and number of servers allocated CPU utilization Storage use Network bandwidth consumed to upload and download data to and from the cloud Management support services provide the information needed to refine the use of cloud services. universal access. For example. standardized platforms. Cloud computing services are not complete without this type of management support services.The Definitive Guide to Cloud Computing Dan Sullivan Management Support Services Cloud computing is not a complete service without management support services. The combination of technologies described in the previous section enable these drivers but are not the drivers to adoption themselves. This brief introduction has just scratched the surface of key aspects of cloud computing. These services support both operational and management aspects of the use of cloud computing. such as massive scalability. we will turn our attention to the drivers behind cloud computing adoption. fine‐grained usage controls and pricing. More details on these topics are provided throughout the rest of this book. but before we delve further into technical details. Operational support services enable cloud users to provision the resource they need without additional support from IT staff. CPU utilization reports may indicate low utilization in jobs that have been spread over more servers than necessary.
By implementing a service‐oriented architecture in the cloud. but it does have some drawbacks: • • • Isolating specialized functions that might be useful in other applications Utilizing a fairly rigid flow of execution making it difficult to adapt to emerging requirements Offering few options to vary service levels according to varying needs Cloud computing readily supports service‐oriented architectures. calculated payroll for the company. Applications processed accounting transactions to balance the books. which can provide a better way to consume services. For example. service to calculate the credit risk of a customer could be used by a customer sales portal as well as a back‐office risk analysis application. and still works well. The same level of fine‐grained control over resource use that the cloud provides at the level of servers and storage is available at the services level as well. Service‐ oriented architectures exchange data and invoke services standards such as Simple Object Access Protocol (SOAP) and frameworks such as Representational State Transfer (REST).5: Services orchestration combines loosely coupled services in a flow of execution designed to complete a logical unit of work. This approach worked well. and generated monthly statements for customers. Each service is implemented in a way that does not require or depend upon knowledge of the way the service is used.The Definitive Guide to Cloud Computing Dan Sullivan A Better Way to Consume Services The early days of IT were dominated by monolithic applications that performed a series of related tasks in a fixed order. Figure 1. customers can consume only the services they need for as long as they need them and be billed only for that use. Service‐Oriented Architecture in the Cloud Service‐oriented architectures use loosely coupled services to deliver functionality. 11 . for some business requirements.
Customers can choose the appropriate level for their needs. and higher‐level services in cloud computing to make service delivery more efficient. This warrants a number of high‐end servers with a single virtual machine instance running the customer's OLTP application. The job could be allocated to low‐end servers early in the night. 12 . storage. or if demand for those is high. More Efficient Delivery of Services There are a number of ways to exploit the fine‐grained controls over compute. • • Cloud computing enables customers to define the level of service they require. The jobs can run at any time during the night as long as the there are sufficient server resources to complete the job in time. For example: • A customer executing an online transaction processing application (OLTP) may need high throughput and rapid response times. Some of the most important are: • • • • Management infrastructure Optimization of workloads across shared infrastructure Self‐service management Monitoring These support services prove to be beneficial for both cloud consumers and providers. can run later in the night but on a number of higher‐end servers. A team of developers performs continuous integration testing every night and needs guaranteed delivery of output at the start of the next business day. allows the cloud provider to optimize workloads across customers and cloud infrastructure.The Definitive Guide to Cloud Computing Dan Sullivan Differentiated Levels of Service The cloud model of computing also supports differentiated levels of service. which in turn. A marketing analyst data mining the results of several campaigns may be willing to have a longer turnaround time in return for running her application on a lower‐cost low‐end server.
Unless there is a steady stream of jobs that fits the machine's configuration. Cloud computing introduces new opportunities for software vendors to change how they price their software. Optimization of Workloads Across Shared Infrastructure A large server farm is indistinguishable from a set of cloud servers when looking at the hardware. switches. there will be idle periods. the customer will lose a significant advantage of cloud computing. Providers can help customers optimize their use of the cloud by providing near real‐ time updates on their resource utilization as well as aggregate billing and charge‐back reports. so a comprehensive management structure can be built on a small number of management services. This makes for a reliable compute resource. reassigned. the cost of switching virtual machines is low enough that idle servers can be reconfigured with different virtual machine images allowing other applications to run on the same physical server that had just been running other types of jobs. Named user and number of user‐based pricing schemes will fit well with cloud computing. Cloud computing supports these requirements with a well‐defined set of basic service components. the cost of reconfiguring a server is so high that it is done only for significant long‐term changes.The Definitive Guide to Cloud Computing Dan Sullivan Management Infrastructure Both public and private clouds support a large pool of potential customers with a wide range of diverse service requirements. or decommissioned. routers. Without proper infrastructure for rapidly deploying virtual machines. Expect vendors to experiment with new pricing models for enterprise software as businesses adopt cloud computing. such as: • • • • • Tracking customer use of virtual servers in terms of number of servers and time used by server Tracking the amount of persistent storage used by customers for a given period of time Accounting for the data transfer into and out of the cloud Accounting for data transfer within the cloud Tracking the use of licensed software This type of management reporting enables cloud providers to bill customers for resources used. A highly‐ parallelized application might run for 10 hours on a single server or in 1 hour on 10 servers. If the software were licensed to run only on a single server. but CPU or core‐based pricing methods are problematic. The servers in a typical corporate data center prior to the advent of cloud computing were assigned to a particular department or application use. These servers were configured to do one type of operation. but not an efficient one. In the cloud. power supplies. Servers with fixed configurations are less likely to have high‐utilization rates. The difference lies in how these resources are used. Servers. The configuration was relatively fixed and changed only when the server was upgraded. and other components are the same. 13 .
The Definitive Guide to Cloud Computing Dan Sullivan Figure 1. provisioning and other management tools are made available to cloud service consumers. server utilization can be significantly higher when workloads are distributed and optimized over available servers. This lowers the cost of delivering cloud services by eliminating or significantly reducing the need for IT professionals to complete allocating and deallocating operations. 14 . Self‐service management also eliminates IT staff availability as a potential bottleneck to using the cloud. Cloud consumers have the tools they need to acquire and use cloud resources themselves.6: In the cloud. Self‐Service Management In cloud computing environments.
realize efficiencies unrealized until this point. Users are free to focus less on maintenance and more on core business issues. however. The economic benefits can be seen in at least three areas: • • • Reducing capital expenditures Efficiently allocating resources Rapidly delivering IT services A common thread among all three areas. Web user interfaces makes this possible. self‐service management. it should be quickly allocated for a new job to maintain maximal utilization rates. a marketing analyst might have an idea for increasing market share for a product in a particular region. 15 . It is important to monitor both the availability of servers and the workloads running in the cloud. other economic factors involved as well. cloud service consumers have more direct control over the resources they use. Changing Economics of IT The economics behind cloud computing make a compelling case for adopting this approach to delivering services. The sales data warehouse makes use of cloud storage. how we deliver services. Evaluating her idea requires a substantial amount of data and compute resources. optimization of workloads across shared infrastructure. After a server has been deprovisioned. is that cloud computing allows us to share computing infrastructure in a way not previously possible and. Cloud computing also improves the user experience by lowering the barriers to experimenting with data or a new business process. and monitoring of cloud resources creates a key driver behind cloud adoption—the more efficient delivery of services. and the way end users experience the use of these services. the cost of procuring or borrowing servers to run this job may have been so high that it was not done. For example. Concerns such as scheduling patches. The combination of management infrastructure. in the process.The Definitive Guide to Cloud Computing Dan Sullivan Monitoring The state of the cloud will frequently change. Cloud computing changes how we consume services. Improving the User Experience through Cloud Computing Another driver behind cloud computing is that it can improve the end user experience. and developing a disaster recovery plan are addressed by the cloud service provider. There are. Without cloud computing resources immediately available. so the data is readily available and provisioning servers is a simple matter with the cloud's Web interface. ensuring security policies are enforced. performing backups. New images are loaded into some servers to execute jobs while other virtual server instances are shut down when jobs complete. These three factors are fundamental drivers behind cloud computing. As noted earlier. Users are also relieved of long‐term management issues when using cloud services instead of dedicated servers. as we will explore in a moment. Simplified.
Consider the following example.The Definitive Guide to Cloud Computing Dan Sullivan Reducing Capital Expenditures An obvious economic advantage of cloud computing from the consumer perspective is the reduced need for capital expenditures. Rather than follow a "pay up front" model. rather than manage many different types of backup jobs that vary according to the needs of dedicated servers. jobs would continue to run on other servers. under the dedicated server model. such as backup and recovery. in the dedicated server model. An online analytic processing (OLAP) application generates weekly business intelligence reports that require a number of high‐end servers to perform all calculations in the time allotted to the process. in the dedicated server approach to consuming compute services. Efficiently Allocating Resources Cloud computing more efficiently allocates compute and storage resources than dedicated server approaches. we have to plan for and purchase for peak demand. the servers are underutilized most of the time. it could simply be removed from the pool of available resources. The source of the efficiency stems from several factors: • • • Ability to manage workloads and allocate jobs to available servers through the use of rapidly deployed virtual machine images to servers with excess capacity Ability to share storage resources and realize the economies of scale with regards to centralized storage services More efficient support operations. The "pay as you go model" is especially advantageous when a consumer would have to purchase servers and storage to accommodate peak capacity but that peak capacity is needed for only relatively brief periods of time. we must plan for disaster recovery separately at the department or project level High availability of service without significant overhead—if a server were to fail in the cloud. a stand‐by server would be needed to act as a backup for each primary server • • 16 . A better option is to use the elastic scalability of the cloud to provision the servers when they are needed and release them when the reports are complete. nonetheless. cloud providers can consolidate backup operations of centralized storage Clouds can be configured to use geographically distributed data centers and replication services between the data centers to provide disaster recovery for all cloud consumers. cloud service consumers follow a "pay as you go" model. In this scenario. Consumers of compute and storage services do not have to procure the underlying hardware that enables those services.
the patched images are deployed Increased self‐service with regards to procuring servers and storage reduce demand on IT personnel More efficient server utilization requires few servers which. under the cloud model. it is a combination of factors. In this case. If demand for a service were to rapidly spike. 17 . The economic benefits of cloud computing emerge in different ways. Functionality developed for one application and delivered through the cloud using service‐oriented architecture can be readily adapted to other applications as well. leads to lower hardware costs and power consumption • • As these examples show. Once again. for example. more efficient allocation of resources. Rapidly Delivering IT Services With a cloud. efficiencies arise both from more efficient allocation of IT assets and of IT personnel. Once again.The Definitive Guide to Cloud Computing • Dan Sullivan More efficient patch management—when servers have relatively fixed OSs. servers can be added to scale to meet demand. this translates into more direct control over how they use services and that can translate into more efficient business operations. the ability to rapidly provision and deprovision compute and storage resources is important. The efficiencies enabled by the reduced time and cost of cloud computing will be maximized only if business strategy is aligned with IT services. including a reduction in the need for capital expenditures. Another consideration is the ability to expand the range of functions provided by IT applications. and the ability to rapidly deliver and adapt IT services. there is no single part of the cloud model that enables this. virtual machine images stored in a centralized catalog can be patched and when new instances of virtual machines are started. businesses can more rapidly deliver services to meet changing business requirements and market conditions. for a retailer during the holiday season. For consumers of cloud services. instead. in turn. each system must be individually patched to keep up to date with security and performance patches. service‐oriented architectures are well suited for rapid reconfiguration of applications through service orchestration (see the earlier discussion of service‐oriented architecture in the cloud).
We may have a clear business strategy mapped to detailed business processes that are ready to implement but still the execution stumbles. more self‐service in systems management. such as hardware failures. or improving the resiliency of IT operations to adverse events. Many of the services needed to support business objectives can be readily identified once the business objectives are known. The gap analysis process should take into account both technical and organizational considerations. Cloud computing and service‐oriented architectures can mitigate the risk of such misalignments. assuming they are used in ways supportive of business strategy. at least at the most coarse level: • • • • Identifying key business objectives Identifying IT services needed to support those objectives Assessing the current state of IT services and identifying gaps between the existing set and the needed set of IT services. or natural disaster. Cost controls and cost reduction come with more efficient server utilization. Developing a plan for reducing the gap between the existing and needed set of information services Key business objectives may include controlling and reducing costs. Why? One reason is that the information systems needed to execute the strategy are insufficient or poorly matched to the requirements. high availability. and disaster recovery. enabling more rapid response to changing market conditions. 18 . and reduced overhead associated with infrastructure services such as backups. but keeping business objectives and IT operations in alignment is not always easy. loss of power. This is certainly not a trivial process. Aligning business strategy and IT services is a several‐step process.The Definitive Guide to Cloud Computing Dan Sullivan Aligning Business Strategy and IT IT serves the strategy of the business. but we will delve into a more detailed examination of the full alignment process in Chapters 5 through 7. For example. improving governance of the organization. will existing hardware readily deploy in a cloud architecture or will new hardware be required? Are service management practices mature enough to implement in self‐service delivery systems? Is a billing or chargeback mechanism in place if a private cloud is under consideration? The first steps in creating a plan to move from the existing to the needed systems are to prioritize the gaps and identify dependencies in the process.
we will turn our attention to demystifying different types of clouds and their characteristics. and business processes. In the next chapter. There are several business drivers behind cloud computing: • • • Cloud computing offers an efficient way to deliver services Cloud computing coupled with service‐oriented architectures improve on ways to consume services Cloud computing improves the end user experience by making it easier to work with services and apply them to new opportunities In addition to these business drivers. dynamic infrastructure Universal access to services from any Internet‐enabled device Fine‐grained usage controls and pricing that allow for more efficient delivery of services Standardized platforms that lend themselves to lower procurement and operational costs Management support services for service consumers to control their use of cloud resources Being able to build with these characteristics is not sufficient to warrant widespread adoption by business. software. such as reducing the need for capital expenditures and efficiently allocating compute and storage resources. Cloud computing is especially beneficial when aligned with business strategy to cost‐effectively and rapidly deliver essential services. there have to be additional drivers behind the technology. 19 . and mature service management practices that lend themselves to a significant level of self‐service all contribute to enable cloud computing. The availability of standardized servers capable of running multiple virtual machines. Cloud computing is different from other approaches to service delivery because of its unique combination of attributes.The Definitive Guide to Cloud Computing Dan Sullivan Summary Cloud computing is a model of service delivery that is enabled by a confluence of advances in hardware. including: • • • • • A massively scalable. standardized virtual machine images for delivering complete application stacks to servers on demand. there are compelling economic arguments for adopting a cloud model.
A Note on Terminology As noted in the first chapter. and the time required to make the server available. before we can realize those efficiencies. The reason we use the same term for different processes is that both apply to making a computing resource available to a specific task. Of course. there are any number of definitions in between. The chapter concludes with a discussion of different cloud delivery models that range from public to private clouds. for example. configured. the duration for which the server is assigned to a specific task. When describing their cloud offering.The Definitive Guide to Cloud Computing Dan Sullivan Chapter 2: Demystifying Cloud Computing The term "cloud computing" has become a shorthand way of describing a wide range of different computing services. Provisioning can also mean creating an instance of a virtual machine.) 20 . We will examine several types of cloud services and the advantages and disadvantages of each. however. still leave plenty of room for different types of cloud computing. to run a job in the cloud for some period of time after which the virtual machine is shut down. The common characteristics. the term "provisioning. This chapter will make those variables clear. The goal of this chapter is to demystify cloud computing by defining a set of common characteristics that should be included in any cloud service that could be considered ready for enterprise use. The key differences are tied to physical versus virtual servers. and deployed to an organization's network. but it is not the only way the term is used when describing cloud computing. provisioning a server almost always meant that a physical server was acquired. Another vendor might use the term "cloud" when promoting a new way to license and run the vendor's applications on the vendor's servers. The elements of cloud computing are not radically new. (These difference underlie the efficiencies cloud computing introduces. we need to be clear about all the variables that are at work with services delivery. Consider. the types of computing services we are describing represent an evolution of information technology and service delivery. for example. as we shall see. a vendor might focus on the ability to rapidly provision instances of virtual machines to run applications of your choice. but we are using and deploying them in new ways." In the past. This can sometimes lead to confusion in terminology. The term still has that meaning.
but they are by no means the only database model available. not days or weeks. Figure 2.1: Massive scalability provides the ability to rapidly increase the amount of allocated cloud resources as needed for a job. We will forgo well‐constrained definitions of cloud computing and instead consider three characteristics that are required to deliver the types of services most of us have come to expect from cloud computing: • • • Massive scalability Ability to easily allocate cloud resources A service management platform There are other characteristics. such as security. provisioning a physical server from provisioning an instance of a virtual machine. Massive scalability. Massive scalability in cloud computing is the ability to deliver significant resources in a matter of minutes. and a service management platform are essential constituents of a cloud computing service. 21 . distinguishing. Relational databases are alive and well in clouds. the ability to easily allocate cloud resources. Describing fundamental characteristics of cloud computing is a step to demystifying this new way of delivering services. for example. configured. The text will also distinguish models of persistent storage when discussing databases. This is not scalability in the sense of purchasing hundreds of servers. and deployed. waiting for them to be delivered. Searching for a Common Definition: 3 Fundamental Elements of Cloud Computing Reasonable people can disagree about precise definitions of new technologies. we will use explicit descriptions. "Systems management" is another term that is adapting to accommodate new tasks that application administrators are expected to handle when working with clouds.The Definitive Guide to Cloud Computing Dan Sullivan Throughout this chapter and the rest of this book. that are entailed within these three and will be discussed shortly. Massive Scalability Massive scalability is the ability to rapidly allocate large amounts of computing resources on demand.
a virtual machine equivalent to an x64 architecture. Computing resources are provisioned for a cloud computing task in different ways. This model has the advantage of giving cloud consumers a wide range of options but at the cost of additional configuration responsibilities. For example. businesses subject to European Union (EU) privacy directives may require that all personal information on EU customers be kept in countries that meet a minimum level of privacy protections. 22 .The Definitive Guide to Cloud Computing Three types of resources should be available: • • • Computing resources Storage resources Network bandwidth Dan Sullivan Computing Resources Computing resources are the means to process information. Run jobs in different data centers to better allocate work load—This functionality is constrained to some degree by business requirements. amount of memory. but that level can vary significantly. Specifications such as this should be considered a logical specification. If there were a single workhorse in cloud computing. there is a smallest unit of computing resource that is allocated. Abstracting computing services can also lead to more efficient delivery. depending on the cloud model. only the most energy‐efficient servers are kept powered on. Execute workloads on physical servers that minimize the distance between the compute resources and the storage resources • • Cloud service providers all abstract some level of implementation details. There may be several operating systems (OSs) to choose from as well as a variety of application stacks. This could be. a cloud consumer may have the option to configure and run a particular statistical analysis package on a preferred version of Linux with this provider. but she is also responsible for tuning and patching this image. Consider a few different scenarios. this would be it. For example. For example. 2GHz CPU dual‐core processor with 32GB of memory and 300GB of local storage. a cloud provider can: • Vary the amount of hardware running at any time according to demand—During periods of peak demand. The (Near) Raw Iron Approach One cloud provider allows consumers to select a type of virtual machine (types vary by number of cores. many large servers may be running while during low demand periods. This is one of the advantages of cloud computing: The details of the physical implementation are abstracted so that the consumer of cloud services does not have to concern themselves with such details. The virtual machine running jobs could be hosted on any of a number of physical implementations. for example. and so on) and the virtual image to run on that machine. At minimum.
The Definitive Guide to Cloud Computing
Dan Sullivan
The Server Role Approach
A second cloud provider may limit the range of options in return for a simplified deployment model. Rather than allow customers to build their own virtual machine images, the cloud provider may offer a small set of preconfigured images designed for specific roles, such as load balancing, running a Web server, or providing application services. Under this approach, cloud consumers could define the number Web servers they need and the number of application servers required without having to concern themselves with OS or application stack details.
The API Approach
Another approach a cloud vendor may provide is a general computing platform that abstracts even basic distinctions such as Web servers and application servers. Under this model, cloud consumers develop applications that use a cloud provider's application programming interface (API), which might include, for example, functions for: • • • • • Defining data structures Creating associative arrays (key‐value pairs) Specifying queries Implementing transactions Utilizing task queues
When the application is run, the cloud consumer need only specify the number of servers to dedicate to the task. By limiting the range of options for implementing an application, the cloud consumer has fewer systems management issues to address. As Figure 2.2 shows, there is a tradeoff between flexibility and systems management responsibility.
Figure 2.2: Cloud consumers have a range of options that balance different levels of flexibility with the need for systems management tasks. 23
The Definitive Guide to Cloud Computing
Dan Sullivan
Storage Resources Massive scalability implies the ability to persistently store raw data and computed results. For the cloud consumer, the amount of storage needed at any point in time should rapidly scale to meet demand. As with computing resources, storage resources should be allocated as needed and there should always be storage available. Cloud storage is available in a few forms: • • • As file‐based storage As block‐based storage in which arbitrary large objects are stored As relational storage in which data is maintained in relational database structures
Data stored in the cloud is manipulated in much the same way as it is in non‐cloud architectures with some minor differences. Block‐based storage may be accessed via URL. Relational data is queried the same in or out of the cloud, but database administrators will have less to manage with regards to the physical allocation of space and replication of data for high availability. Network Resources The ability to move data from compute to storage resources must scale along with those resources. Within the cloud, the network capacity and infrastructure is defined and managed by the cloud provider. Providers can reasonably plan for moving data from servers to storage arrays or replicating data between storage devices. The situation changes when data has to move into or outside of the cloud. Cloud service providers are more constrained in their ability to deliver network scalability because of dependence on the outside networks. Cloud consumers transfer data into and out of the cloud using whatever network services they have acquired. This may or may not be sufficient for the volumes of data that need to be transferred. In response, some cloud providers offer "sneakernet to the cloud" services: physical storage devices are shipped to the cloud provider where they are uploaded to the cloud. Part of optimizing cloud‐based services is determining the best way to move data into and out of the cloud and minimizing transfers outside the cloud. The network bottleneck is one reason to generate, process, and store data in the cloud as much as possible. Massive scalability is a fundamental characteristic of cloud computing. Cloud providers offer different approaches to providing computing resources that tradeoff between flexibility in applications that can run in the cloud with demands on cloud consumers to manage system resources. Similarly, massive storage scalability is fundamental to cloud computing. At this point in time, networking resources outside the cloud are a potential bottleneck to moving data to and from the cloud.
The Definitive Guide to Cloud Computing
Dan Sullivan
Ability to Easily Allocate Cloud Resources
Cloud computing can significantly reduce the need for systems administration support by providing easy‐to‐use tools for allocating cloud resources. One of the advantages of abstracting many implementation details is that it allows for greater automation of the cloud resource provisioning. As noted earlier, cloud providers offer different levels of abstraction of services, but in all cases, the provider should offer tools that enable application administrators the ability to adjust the usage as demand dictates. Consider a simple example. A marketing analyst has just acquired several large data sets on product sales over the past several months. This is a onetime task and the analyst needs to aggregate the data for business reporting as well as run some statistical analysis programs over each data set. Outside the cloud, the analyst would need to perform several time‐ consuming steps: • • • Find a department server with availability and convince the owner to allow the jobs to run on that server. Next, assuming a server is found, the analyst would then submit a ticket to systems administrators to install the necessary analysis software. When that is done, which could be a few hours to a few days depending on the IT support backlog, the analyst would need to upload the data. If the data is compressed, additional storage will be required to store both the compressed and decompressed files until the decompress operation is complete. Run the analysis jobs. This is a compute‐intensive job, so the time to complete it will depend on the number of CPU resources available. If the analyst was provided with a virtual server running on a host with several other virtual machines, the workloads on the other virtual machines can adversely impact the data analysis job.
The same process in the cloud is significantly less arduous. • Select a virtual machine image to run on cloud servers from a catalog of images. These can range from OS‐only images to complete development or analysis environments. Specify the number of the virtual instances to run. In some cases, cloud vendors may offer options on the size of servers (for example, small, midsize, high‐end), in which case, the size would need to be specified as well. As multiple servers are available, the analysis job can be subdivided into smaller jobs and run in parallel. Load the data into cloud storage and decompress if necessary. Run the analysis jobs.
• •
These steps would be performed in a Web browser using a resource management interface by the analyst. There is no need for specialized IT support, no need to search for a server with available capacity, and no need to allocate disk space to a file system. The combination of massive scalability and easy‐to‐use interface to allocate resources provides two of the three core elements of cloud computing. The ability to manage services is the other.
The Definitive Guide to Cloud Computing
Dan Sullivan
Service Management Platform
Once we move beyond simple scenarios like the one previously described and start to consider enterprise‐scale management issues, the need for a services management platform becomes clear. A cost‐effective cloud service will offer a management platform that supports four aspects of service management: • • • • Support for automated provisioning and deprovisioning of resources Self‐service interface A service catalog of standardized services Policy definition and enforcement
Support for automated provisioning and deprovisioning and the self‐service interface were covered in the previous section, so we will focus our attention on the other topics here. Service Catalog of Standardized Services A service catalog introduces consistency and reusability to the cloud. A catalog includes virtual machine images that can run within the cloud with minimal setup on the part of the cloud consumer. These images capture design patterns that have worked well in other use cases. For example, a basic Web server service might include the latest version of the Apache Web server, a fully patched and hardened Linux OS, and a properly configured firewall. Another image in the service catalog could provide an extraction, transformation, and load (ETL) application for use with data warehousing applications. With the ability to instantiate a fully functional ETL system in a matter of minutes using a self‐service interface, the barriers to entry to business intelligence and data analytics is significantly reduced. Policy Definition and Enforcement A service management platform can ensure that operations in the cloud comply with organization policies. Technical policies can address issues such as: • • • Authentication and authorization required to use resources Resource limits, such as the number of concurrent virtual servers a user can have instantiated during peak load periods Pre‐instantiation checks, such as ensuring images are properly patched before executing or virtual machines use currently approved versions of supported OSs
These include: • • • Dan Sullivan Adjusting the cost of using resources according to demand—This could be implemented with a policy of peak load pricing or bidding based spot pricing. at least for The Definitive Guide to Cloud Computing. A Cloud by Any Other Name Cloud computing has the potential to significantly reduce costs and improve the delivery of business services. Prioritizing workloads in the event sufficient resources are not available during peak demand periods Controlling the number of instances of a particular application that is running at any one time—This is would be used to ensure compliance with software licensing agreements A service management platform is essential to reducing labor costs associated with delivering information services. Simply calling a service offering a "cloud" is not enough. Figure 2. easy to allocate resources. 27 . This guide has and will continue to argue that cloud computing entails massive scalability. and a service management platform that includes a service catalog.3: Cloud computing requires three fundamental elements to be effectively used in enterprise computing.The Definitive Guide to Cloud Computing Organizational policies can be enforced as well. These three elements are essential to offering a viable cloud computing service in an enterprise. It is no wonder vendors would want to offer something in this area. It enables non‐IT professionals to allocate resources they need when they need them while still ensuring organization policies are followed.
28 . driving up costs in turn. the lack of which would drive up costs of creating and maintaining virtual machine images. Traditional service delivery models would continue to exist and undermine the cost benefits of cloud computing. Different Types of Cloud Computing Services Cloud computing can encompass a broad range of services. These services range. This type of service is the one used as a model in the previous section describing the three defining characteristics of cloud computing. there would not be the resources required to meet fluctuating demand. Here we will turn our attention to describing how this type of service can be used along with an example use case to show how cloud computing can significantly improve some types of service delivery. Cloud computing lends itself to a wide array of services and service delivery models. As we will see in the next section. to include: • • • Infrastructure Platform services Application services Each level of service meets a distinct set of needs.The Definitive Guide to Cloud Computing Dan Sullivan If any doubts remain. Billing and resource management would require more manual processes. Cloud consumers would have to have backup resources in place in case cloud resources were not available. creating the potential for backlogs and driving up labor costs. Without easy provisioning. Without massive scalability. in increasing order of specific type of service. leaving the potential to violate governance and compliance regulations. there are many ways to provide cloud services. IT support would not have a mechanism to enforce policies. so it is not surprising to see a number of broad options emerging. Without a service management platform. cloud consumers would not have a well‐managed service catalog. Infrastructure Services Infrastructure services deliver computing and storage services. cloud consumers would still have to depend on IT support. consider if any one of these three characteristics were missing.
power to keep a minimal infrastructure running. a business could: • • • Maintain a set of virtual machine images that would run the business applications in the event of a disaster Maintain copies of data in cloud storage using an appropriate combination of backups and near‐real‐time replication Establish a plan for provisioning cloud services to meet disaster recovery requirements. This type of cloud service also works well for accommodating peak demand periods for either standardized applications or proprietary workflows. cloud consumers can run proprietary workflows that do not depend on preconfigured services. which users could instantiate and then add custom applications to complete the set of components needed for the workflow. is to use a cloud provider as a disaster recovery service. some services may be run on smaller. For example.The Definitive Guide to Cloud Computing Dan Sullivan Computing on Demand The ability to provision computing resources for just about any computing requirement is valuable enough to drive the adoption of cloud computing even if none of the other types of cloud computing services were available. Existing infrastructure may be sufficient for average loads. and therefore lower‐cost. computing on demand can be closely coupled to storage on demand. There may be marginal labor costs as well to maintain the site. Maintaining a disaster recovery site can add significantly to the cost of providing a service. for example. but during peak periods. the service catalog would have virtual machine images with OSs and application servers. businesses pay for the housing equipment. With computing on‐demand services. A broad set of service images in a service catalog can provide a starting point for building proprietary workflows. and maintaining servers and other equipment. and one enabled by the computing on‐demand model. 29 . To do this. as these requirements demonstrate. Even if a disaster recovery site is never used. servers while in disaster recovery mode Of course. An alternative. such as the holiday shopping times in the retail industry. additional computing services may be needed for relatively short periods of time. organizations have the ability to allocate virtual machine resources for a variety of tasks: • • • • Executing proprietary workflows Meeting peak demand for computing Performing disaster recovery Running highly distributed applications By allocating just basic computing services.
Demand for storage can vary widely. but without an option such as cloud‐based storage on demand. timecritical operations like aggregating data for business intelligence reporting. In some cases. data can be uploaded from multiple local sources simultaneously. especially when the ETL phase has to occur in a limited window of time. an accounting firm may have peak demand for 2 to 3 months prior to tax‐filing deadlines when large amounts of data are coming into the firm. After the deadline. Figure 2. When dealing with multiple remote sites. Collecting and processing this data can impose significant demands on computing and storage resources. Cloud storage offers the ability to protect backups from site‐specific damage but without the need to maintain another physical site.4: With ondemand computing and storage. That data is then aggregated at low and mid levels in parallel before being aggregated at a global level and finally stored in a cloud database for later report generation. can be done in parallel. the need for storage is fairly consistent. For example. or relational storage to meet a variety of requirements.The Definitive Guide to Cloud Computing Dan Sullivan Storage on Demand Storage on demand can provide file. The wide potential for on‐demand computing and storage can be demonstrated with a more generally applicable example as well. such as the need for offsite backup. 30 . the firm would have to maintain peak storage capacity all year. With on‐demand computing and storage. data can be archived and moved off disk. copying backups to the cloud can be an appealing option rather than physically transporting tapes from those sites or maintaining additional disk storage at a data center to accommodate those backups. block. This ensures the job completes within the allotted time. Business Intelligence Use Case Business intelligence reporting is driven by large volumes of up‐to‐date information.
One of the latest advances is the ability to host relational databases in a cloud. One method is suitable for small projects with short life spans. Running the operations with cloud resources eliminates the need for maintaining dedicated servers that would otherwise be underutilized. Figure 2. the other takes advantage of cloud infrastructure for a more scalable solution. the platform services delivery model may be a better fit. it is worth noting that there are two ways one could host a database in the cloud. Relational Database Services Relational databases are the data backbone of most enterprise applications. Infrastructure services are an appropriate delivery model when organizations require basic computing and storage resources. Continuous improvement in relational database management systems have allowed relational databases to keep up with growing and changing demands for managing persistent data. developing.The Definitive Guide to Cloud Computing Dan Sullivan Running the aggregation operations in parallel allows the process to complete faster than if done sequentially. Platform‐based services include tools for designing. such as relational databases and application security services that span multiple layers of the application stack. relational data models have offered significant advantages over other database frameworks. 31 . Platform Services Platform‐based cloud services deliver higher‐level services than the infrastructure‐based model offers. To avoid any confusion. Since the later 1970s.5: Platform services (in green) provide application development components built on lowerlevel cloud services. and deploying applications using a set of supported application components. When those needs include components commonly found in application stacks.
a database administrator provisions a virtual server and installs the database management system on that server using local disk storage for database files. Unless the instance hosting the database is kept running. within the cloud. across multiple disks to optimize performance Monitoring I/O patterns to detect bottlenecks in disk operations Replicating data to ensure high availability since persistent data is typically written to multiple locations within cloud storage Of course. the database will be lost. relational database services attend to a number of low‐level implementation details that are typically the responsibility of a database administrator. expect cloud providers to support the three fundamental characteristics of cloud computing with respect to relational databases: massive scalability. easy to allocate resources. and a service management platform. One of the advantages of the cloud is that virtual machine instances are started and stopped as needed. it is not what is generally considered a relational database service. 32 . Database administrators working with relational database services can focus more attention on the logical aspects of database design: • • • • Defining schemas Optimizing indexes Tuning stored procedures and triggers Creating views and other abstractions to better support application development Also. Relational Database Services Optimized for the Cloud Relational database services for the cloud take advantage of the scalability of compute and storage resources of the cloud. this does not mean the end to database administrators as we know them any more than cloud computing is putting an end to systems administration. Another drawback is that the versions of relational database management systems running on typical enterprise servers are not designed to take advantage of cloud storage services based on allocating blocks or buckets of storage for arbitrary data. Under this method. such as tablespaces. For example. One drawback is that local storage is allocated to a user's virtual machine instance only as long as the instance is running. Although this is one way to use relational databases in the cloud. As one might expect.The Definitive Guide to Cloud Computing Dan Sullivan A Simple Relational Database System in the Cloud The first method basically transfers the same approach to database management we typically use outside the cloud and applies it in the cloud. This approach may be suitable for limited needs but is not a general solution for persistent relational storage in the cloud. database administrators do not have to concern themselves with: • • • • Managing disk space Specifying how to distribute low‐level data structures.
Security is a product of specialized components. This ensures the components can take advantage of scalability. middleware applications. include support for: • • • • • Authentication Authorization Auditing and reporting Key management Security token management Authentication and authorization are necessary to determine who is using a system and limiting what they are allowed to do. Application Services Today's complex enterprise applications are often built on application frameworks and design patterns. high‐availability. simply use the same security procedures in the cloud that we use outside the cloud anymore than we can simply run a database management system built for a single server in the cloud and expect cloud‐like benefits. as well as systems design. a cloud provider may offer a framework specifically designed for the cloud and not available in other architectures.The Definitive Guide to Cloud Computing Dan Sullivan Application Servers Application component services provide middleware services in the cloud. so it is not surprising to see support for these in the cloud. development frameworks. Above infrastructure services and platform services in the hierarchy of cloud services. such as application servers and portal servers. at a minimum. 33 . Auditing and reporting are required to ensure policies and procedures are enforced and to detect unauthorized activity as soon as possible. The fundamental principles of security are no different in the cloud than outside the cloud. we find applications. Security services need to be embedded into cloud platform services and. especially if providers specialize in supporting one type of framework. We cannot. The frameworks vary but include components such as runtime libraries. In some cases. Like relational databases. however. The level of support for different frameworks will vary by cloud provider. and other security services on their behalf. such as authentication and authorization services. authorization. can be optimized for the cloud. and service management platforms provided in the cloud. and higher‐level application components. Key management and security token management are especially important in distributed systems where multiple systems depend on trusted identity management systems to perform authentication. Security Services Security is not a component one can isolate like a database or a messaging queue.
another instance can still read the request because it is not deleted from the queue until the response is generated. If a single instance of the backend server is down. Messaging Queues Messaging queues provide for asynchronous communication between processes running in the cloud. If one of the backend instances crashes while processing a request. Figure 2. In a tightly coupled application. the request can still be serviced. and accommodating the failure of a component within a distributed system. implementing distributed transactions. messaging queues enable more robust application design. then delete the request. the interface would submit the request to a queue.6: Tightly coupled systems are more likely to have single points of failure. Application services within the cloud also include higher‐level components that enable enterprise application functionality. Consider as an example a Web interface running on one server accepts requests from users. the interface may pass the request to one instance of a backend service and wait for a response. Two such services are messaging queues and support for highly distributed. 34 . Any one of a number of instances of the backend service could read the request from the queue. If the backend service is down.The Definitive Guide to Cloud Computing Dan Sullivan Even with variation in frameworks and programming languages. parallel processing. In a loosely coupled design. respond to it. a number of application services may be available that allow programmers to take further advantage of what a cloud infrastructure has to offer. the application fails. Messaging is useful for constructing workflows.
Take for example. can be divided into even larger numbers of sub‐problems. analyzing click‐stream data. A map‐reduce approach to this problem could be defined as follows: • • • Split the set of all click stream data by customer session Partition the customer sessions across 100 instances of the analysis program For each customer session. this is a good candidate for highly parallel analysis. 35 . reviews that were read. The basic idea behind map‐reduce is that some problems are inherently parallel: Some steps in the computation can be done independently of other steps and the results of individual computations can be combined to produce the final result. reviews. and navigation paths taken to the point where a product was added to the cart. A programming paradigm known as map‐reduce is one suitable‐for‐clouds method to implement parallel applications. As one customer's activity is independent of others. That problem can be broken down into a small number (for example. thereby creating the possibility for greater amounts and more in‐depth analysis of customer interaction behavior. look for types of pages. Other problems. This introduces opportunities for performing operations in parallel that would normally have to be done sequentially when only a small. A business is analyzing patterns of activity on their e‐commerce site to determine whether there are common characteristics shared across customer interactions in which the customer abandons his or her cart. especially those with large amounts of data. on the order of 10) steps followed by an aggregation process to combine results. The click stream data from the Web site contains information about what products the customer viewed.The Definitive Guide to Cloud Computing Dan Sullivan Distributed. The ETL example cited earlier highlights a problem with course‐grained parallelism. search results—this is the map phase Combine the results of each map phase to produce the aggregate number of times each pattern occurred—this is the reduce phase • A key advantage of this approach is that large volumes of click stream data can be analyzed much faster in parallel than sequentially. Parallel Processing One of the advantages of cloud architectures is access to a large number of servers. scan the click stream for the number of times each possible 3‐page sequence pattern occurs. fixed number of servers are available. such as product details. to simplify the pattern.
Application middleware.The Definitive Guide to Cloud Computing Dan Sullivan Figure 2. With the commonly used "one server/one application" approach that has been used for years. For example. businesses may find themselves limited to how many users they can support with these applications. are all enabling components for delivering enterprise applications in the cloud. 36 . The company then merges with another business that also needs CRM support. can enable organizations to reduce the number of separate instances of applications running throughout the enterprise. Applications and Business Services Providing application and business services from the cloud presents an opportunity to consolidate those services. The IT staff of the new company will have to determine whether a single server can support the newly merged enterprise or multiple instances of the system will have to be run. The beneficial features of cloud computing. like map‐reduce that exploit the parallel capabilities of a cloud. such as flexible scalability and a service management framework. such as application servers. design patterns. such as the use of messaging queues for asynchronous communication across multiple processes within a cloud. As cloud technology adoption grows.7: Mapreduce is a parallel programming framework that works well with cloud computing and storage. we can expect to see more enterprise applications being offered directly to cloud service consumers. The latter option can lead to fragmentation and arbitrary divisions that in turn can lead to organizational problems down the road. and programming frameworks. consider a company that runs a CRM application on a server sufficient for current needs as well as some moderate growth. Consolidating Enterprise Applications Consider a few common types of enterprise applications: • • • Customer relationship management (CRM) Enterprise resource planning (ERP) Business intelligence Each of these types of applications can have broad reach throughout a business.
and Southeast Asia customers in one instance. Africa.The Definitive Guide to Cloud Computing Dan Sullivan Let's assume the business decides that running two instances of the CRM application is the more cost‐effective alternative. With standardized virtual machine images and centralized cloud storage. Middle East. there will be a need to manage according to service level agreements (SLAs) and other expectations for performance and availability. Moving enterprise applications such as CRM. On the management side. As data is consolidated in the cloud. This will require both technical and management approaches to the problem. additional compute resources can be brought online as demand for services grows. application administrators will need to utilize performance reporting provided by the service management platform to ensure SLAs are met in cost‐effective ways. There is no point running six instances of an application with an average server utilization of 25% when running three instances still leaves plenty of margin for spikes in demand without the need to instantiate another virtual machine image. and accounting issues. and Europe. transnational companies be divided? Will regional subdivisions of customers be separated? How costly and time consuming will it be if the allocation of customers has to be re‐ arranged to align with new business strategy? What is required to support a federated identity management system so that users in one system can access the other system as needed? Similar questions can be asked about ERP systems. increased software licensing costs. This may be the most expeditious approach in the short run but over time it can lead to duplicated data. and business intelligence systems to the cloud can help reduce costs and improve the delivery of business services. Departments with more limited requirements may build locally managed data marts employing easier‐to‐use databases and reporting tools. ERP. such as data marts. South America. A host of questions arise: • • • • How should customers in global. inventories. On the technical side. the questions would focus on budgets. instead of customers though. we can avoid data fragmentation problems. The customers are divided geographically with North America. fragmentation can occur around tools and procedures. Managing Business Services and Workloads As applications move to the cloud. 37 . In the case of business intelligence. Standardized virtual machine images deployed through a services management platform reduce the demand for specialized database and systems administration expertise in departments running local applications. and redundant administration costs. Running multiple instances of an application and load balancing across those instances can help maintain performance and provide a level of reliability to the system. we need to be cognizant of utilization. Enterprise‐scale data warehouses may have dedicated database administrators who are able to tune and manage complex database management systems. financial projections. and other Asia customers in the second instance.
so did the delivery models to the point where we have at least three distinct delivery models: • • • Public clouds Private clouds Hybrid clouds Public and private clouds have advantages and disadvantages. we will likely see a variety of pricing models. One remaining dimension we should consider is the public/private cloud distinction. hybrid clouds attempt to capture the best of both worlds. there are many ways to leverage cloud services and the benefits generally arise from a set of common attributes. and a service management platform—describe key architectural elements of computing and storage clouds. Common Attributes of Cloud Service Models The three defining characteristics of clouds—massive scalability. Cloud Delivery Models When cloud computing first emerged as a viable platform.The Definitive Guide to Cloud Computing Dan Sullivan It is clear as we consider the different types of services. 38 . and manage computing. allocation is driven by immediate demand not the need to maintain capacity for peak demand Flexible pricing—Cloud providers typically charge with a "pay as you go" model. storage. from infrastructure to platform to application services. A consumer of cloud services may see a different set of attributes from their perspective: • On demand self service—The ability to allocate. use. in terms of services delivered. resource pools enable redundancy and reduce the risks of single points of failure Elastic scalability—Cloud consumers decide how much of any resource they utilize at any time. application. As cloud computing expanded. and other business services at will without depending on IT support staff Ubiquitous network access—The ability to work with cloud resources from any point with Internet access. the term generally applied to what we would now call a public cloud. as cloud computing matures. and from the perspective of a cloud consumer. cloud service consumers are not dependent on being in corporate headquarters or in a data center to have access to an enterprise cloud Location independent resource pools—Compute and storage resources may be located anywhere that is network accessible. including prices that vary by level of demand • • • • We have described cloud services from an architectural view. easy to allocate resources.
Finally. Another disadvantage is that businesses are dependent on the viability and reliability of the cloud provider. a portion of the public cloud is treated as an extension of the private cloud. This delivery model can be especially appealing when compliance. a hybrid model could be a better alternative. and these costs can easily grow beyond the cost of computing and storage for high‐transfer rates. To realize the greatest benefit of the cloud architecture. security. The two clouds could be separately managed service platforms. and the best option in any situation is highly dependent on specific requirements. There may be cases where the public cloud is less expensive or can provide capacity unavailable on the private cloud. there is more than one way to deliver a service. An immediate advantage of using a public cloud is that there is no upfront capital expenditure required of business users. Another way to manage the hybrid private‐public cloud is to enable access to the public cloud from within the service management platform. Cloud consumers purchase computing and storage services as needed and pay as they go. Policies are established to govern what kinds of jobs can run in the public cloud. Private Clouds Private clouds are owned and operated by businesses for their internal use. There are a few different ways to do so. A private cloud does require capital expenditure to procure hardware and software for the cloud. multiple data centers will implement distributed storage and compute infrastructure. 39 . and define its own service catalog of virtual machine images for use in the cloud. A business could find a successful private cloud creates demands that exceed current capacity. Capacity planning is also an issue. control access. This approach gives cloud consumers freedom to choose between two services. A staff of IT professionals must also be available to administer and manage services. As is so often the case in information technology. If there is a significant service outage. but they are especially necessary when critical business services are dependent on third parties. and other risks factor significantly when developing a cloud strategy. Expanding a private cloud can require substantial capital expenditure. and cloud consumers have the option to run and manage their jobs in the public cloud. There are likely costs associated with transferring data to and from the cloud. Under this model. the public cloud could be treated as an extension of the private cloud by implementing a virtual private network (VPN) in the public cloud. The two services are still independent. Hybrid Clouds A hybrid cloud combines public and private clouds. Risk assessments and mitigation strategies are called for when working with any cloud.The Definitive Guide to Cloud Computing Dan Sullivan Public Clouds Public clouds are computing and storage services that are open to any consumer. A key advantage of a private cloud is that the business is in control of the service: it can set pricing and policies. data and services will be inaccessible. but cloud consumers would have a single point of management. A business that has implemented a private cloud can use public cloud resources as an extension of their own cloud.
cloud providers can deliver a range of services. and delivery methods. architectures. from infrastructure to platforms to applications and business services. service models. and hybrid clouds offer a range of options suitable for many business requirements. ease of allocating resources. and a service management platform. including massive scalability. private. it has managed to create a host of competing definitions. 40 .The Definitive Guide to Cloud Computing Dan Sullivan Summary Cloud computing is relatively young. but in the short time since its inception. Building on this foundation. No single delivery model meets all needs. but the combination of public. Across all of these varying ways of looking at cloud computing. we find common characteristics.
Advantages of doing business with cloud computing—The advantages of doing business with cloud computing include the reduced time required to deliver new services. After all. Sources of ROI in the cloud—ROI in cloud computing comes from both reduced capital costs and lower operational costs. cloud computing is not an end in itself (unless you are a computer scientist or systems architect) but a means of delivering existing services more efficiently and enabling the delivery of new services that may not be practical under other models. the ability to scale to demand. As a first step to understanding the source of ROI in cloud computing.The Definitive Guide to Cloud Computing Dan Sullivan Chapter 3: Enabling Business Innovation by Using Cloud Computing Many discussions of cloud computing focus on its technological advantages—and there are many—but there are business advantages as well. As with other technologies. • • 41 . and the adaptability of cloud computing. Example scenarios will illustrate some of the key differences. The chapter is divided into three main sections: • Launching a new business service—The first section compares service delivery under traditional IT service models and under cloud computing. how you implement and manage cloud services contributes to how much of the potential ROI is actually realized. the ROI in the cloud is highly dependent on more than just the technology. new means to control costs. This chapter shifts focus from questions of architecture and operations to issues of service delivery and return on investment (ROI). let's consider a couple of hypothetical examples of how service delivery in the cloud differs from traditional IT service delivery.
must also be in place to ensure proper operations. Skimp on usability engineering or otherwise shortchange the user interface. 42 . you will see how some of these potential problems can be reduced. Those of us who have worked on projects with inadequate planning know the frustration and futility that come with ad hoc. and the service can degrade to the point of failure. Once a service is deployed. Take away sufficient computing. rework. Procedures.The Definitive Guide to Cloud Computing Dan Sullivan Launching a New Business Service There is nothing like launching a business service to combine the exhilaration of creating something new with the apprehension associated with choreographing all the elements required for a smooth launch. it is time to move into an operation maintenance mode. cloud computing is no panacea and no amount of technology can compensate for poor management practices. even with the best planning and policies in place. storage. Of course. or networking. and missed steps could have been avoided. Planning is just as important here as it was during design and deployment. and you lose customers at the proverbial front door. Needless to say. storage. The worst part is that the delays. The difference is that now you shift from a project planning framework of deliverables. As we consider the advantages of cloud computing for service delivery. hardware fails. which turn those polices into executable tasks. reduce some of the burdens and challenges that typically come with planning and implementing new projects. and natural disasters strike. can help you respond effectively and efficiently when adverse events occur. software errors manifest themselves. And there is no shortage of pieces that must be in place: • • • • • The computing. Policies governing everything from service level agreement (SLA) monitoring to backups to security should be in place at launch. and network services required to support the service Software that captures the functional requirements of the new service while providing a usable interface A well‐developed plan for deploying elements in the proper order so that dependencies are in place as new components are put in place Policies and procedures to govern how the service infrastructure is managed and maintained A recovery strategy and corresponding systems to mitigate the risk of data loss or service delivery failure It is easy to see how essential each of these technical and business elements is to the ultimate success of the project. however. A recovery management strategy. Cloud computing can. commensurate with the value of the new services. milestones. and resource balancing to operations guided by policies and procedures that define what is to be done and how to do it. reactive management.
What is the best service delivery model for realizing project objectives? Figure 3. disrupt. or undermine any of these. 43 .1: Service delivery is built on a foundation of technology and business services and practices. These examples are chose for several reasons: • • • • They are significantly different types of services—one is a customer‐facing Web application and the other is a more batch‐oriented back office service They require a different combination of computing resources They have different usage patterns over time Cloud computing can reduce the cost of delivery of both services regardless of the differences in the type of application an demand profile First. we will consider a home improvement retailer with a plan to offer tutorial videos on home improvement projects for the do‐it‐yourself (DIY) customer. Next. successful service delivery is dependent on these and other technical and business factors. In our second example. Remove. To better understand how service models influence service delivery. One of the questions facing business strategist and systems architects is. and services delivery is adversely affected.1 depicts. let's explore the steps involved in deploying these two services under a traditional IT service model.The Definitive Guide to Cloud Computing Dan Sullivan As Figure 3. In the first example. we will see how business analysts deal with the problem of "big data" and the need for advanced business intelligence and analytics services. let's assess delivering a couple of different types of services under different models. we'll look at how the same service could be deployed in the cloud.
Videos will range from 1 to 10 minutes in duration with an average of 5 minutes. • • • • • • Using current Web site statistics. and time to complete the task. but some of us think we could do a fairly decent job around the house if we just had the right tools and a few tips to get us started.2. and deployment practices are well developed under traditional IT service models. at the end of the beta testing phase. 1000 videos will be available. The results will be analyzed to improve the overall quality of instruction. A home improvement retailer that has traditionally done well serving the small contractor segment of the market has decided to target the potential DIY customer in an effort to improve sales and expand their share of that market segment. 44 . Videos will be accessible through a centralized "How‐to Video Library" in the Web site as well as through product pages that link to relevant videos. such as repair type. After that. The following list highlights key features and non‐functional requirements: • The service will provide short tutorial videos on a range of home improvement topics. testing. Mid‐Atlantic. expand the scope of topics. software development. it will be made available throughout the company's North American market. They all come into play in our two hypothetical scenarios. Metadata will be assigned to each video to improve search and browsing.The Definitive Guide to Cloud Computing Dan Sullivan New Services Under a Traditional IT Service Model Project management. The anticipated demand pattern is depicted in Figure 3. and Southeast United States. Unstructured data describing the video content is also included. The initial launch will support up to 500 videos. The service will be launched in beta to customers in the Northeast United States for 4 weeks followed by an extended 4‐week beta to the Northeast. Videos will be streamed over the Web and delivered through the company's Web site. Customers will be encouraged to review and rate videos. Scenario 1: Tutorial Videos for the DIY Customer Not all of us are gifted carpenters or skilled plumbers. business planners anticipate peak demands Wednesday and Thursday evenings between 6:00pm and 10:00pm and Saturday mornings between 7:00am and 11:00am. and eliminate the least‐useful content. Content will grow at an average rate of 200 videos per month after that. tools required. Tags will include structured data.
45 . As the systems architects and application designers plan the infrastructure for this service.2: Service demand will vary widely by day of week and time of day.The Definitive Guide to Cloud Computing Dan Sullivan Figure 3.3 shows the configuration. so they resort to the next best thing: making a best guess estimate and then add another 20% for contingency. The major components they decide on include: • • • • Several servers to stream the video tutorials A load balancer to distribute user sessions across several servers A storage array with sufficient redundancy (for example. On the business side. They do not have sufficient data to confidently predict demand for the service. (Times are relative to the time zone of the data center hosting the service). this project will require a capital expenditure and C‐level approval. The irony of running a "how to fix" tutorial service on a poorly functioning platform could undermine the brand image and is not worth risking. they have to take into account a number of considerations. although those periods are relatively few and fairly short. RAID 6) Application licenses to support the service Figure 3. The service will require servers to meet peak demand. The combined concern for not performing to customer expectation with the inability to get a second round of resources rapidly enough push the applications designers and systems architects to choose a more costly solution than may ultimately be required. The IT professionals on the team know that they will have one chance to get the resources they need within the next 12 months.
after all. From a competitive perspective. premiums have to correlate with risks. there are many factors to consider. 46 . As with any type of insurance. For auto insurers.The Definitive Guide to Cloud Computing Dan Sullivan Figure 3. competitors use the same data. primary garaging location of the vehicle.3: The video tutorial service requires hardware to meet peak demand even though the average demand is significantly less. Using the same data can lead insurers to cluster drivers into similar groups making it difficult to compete on price within those groups. It is clear from this example that building out this service following a traditional strategy requires that you build for peak demand before you even have sufficient information to determine the actual level of need. past accidents. including the age and sex of the driver. Not only can you not adjust to changing needs. number of moving violations. Scenario 2: Advanced Analytics for Auto Insurance Premium Calculations The auto insurance industry is a competitive business. you have to make a fairly long‐term commitment to the architecture early in the process. and so on. using just these factors is insufficient to gain any competitive advantage.
and so on. and so on must be available for data mining Additional data on household income. Ultimately. primary garaging location of the vehicle. internal and external data will be collected and analyzed to build a predictive model that categorizes each customer by fine‐grained risk estimate • • 47 . and so on. past accidents. Figure 3.The Definitive Guide to Cloud Computing Dan Sullivan In this scenario. disposable income. household net worth. this could reshape the risk pool by attracting better drivers with lower rates than competitors offer while giving incentive to higher risk drivers to look elsewhere for insurance. recreation. several auto insurance analysts propose expanding the base of data used to categorize customers and then applying data mining techniques to create finer‐grained clusters of customers. including income by age. disposable income. and publically available data. number of moving violations. automotive. such as financial services. Premiums can be adjusted to these finer groups of customers so that customers posing greater risks can be charged higher premiums allowing for lower premiums for safer drivers. business activity data by location. The following list highlights key features and non‐functional requirements: • Existing data sets on age and sex of the driver.4: Finergrained clustering of customers can create a competitive advantage by allowing more precise and accurate premium pricing. medical. consumer spending data by category. including census data and crime statistics On a monthly basis.
architects will have to purchase storage sufficient to support copies of all the various data required. the models will be executed on to categorize new customers and reassess the premiums on existing customers during policy renewal. The cloud computing model offers an alternative method for deploying services. Once again. Capital spending decisions may have to be made with insufficient usage data. transformation. Both of these scenarios manifest common difficulties with the traditional IT model of service delivery. • This application is compute intensive during the times when the data mining systems are running and predictive models are being created. this service requires that you build an infrastructure for peak capacity. Running models are significantly less compute intensive than generating them. Although data will only need to be stored during the time the models are built. Dedicated resources are not used efficiently. data will not be stored once the model is constructed To improve the quality of predictions. Figure 3. multiple prediction models will be constructed and results will be combined to make final classifications. After the models have been created. A cluster of high‐end servers each with multiple multi‐core CPUs and significant amounts of memory are required to build the individual predictive models combined into an ensemble prediction service.The Definitive Guide to Cloud Computing • Dan Sullivan New extraction. and load (ETL) procedures will be developed to collect data from multiple sources and copy it to project storage. 48 .5: Analytic operations have fairly predictable demand patterns that include significant periods of peak demand followed by analysis operations. It is difficult if not impossible to scale the infrastructure up or down according to demand.
based on the type of source data and it's configuration. Rather than focus on predicting what the peak demand will be over the next 12 months. In this case. With virtualization and service catalogs. this is a simple matter. Planning for long‐term storage is not a significant issue because additional storage will be allocated as needed. the raw data is deleted. when they need them. however. you can run the workflow as a sequence of steps allocating servers for each step as needed and then shutting them down and starting servers with software for the next step. they write data to cloud storage. the virtual machine image management would be more difficult without a service catalog and it would still not address the problem of having to purchase hardware for peak demand. 49 . there is a recurring demand for a significant amount of storage and computing resources. such as ETL systems. and pre‐ processing scripts and statistical and data mining packages Instantiating servers to run parts of the workflow as needed. The demand is for only a few days every month. Initially. systems administrators will adjust as needed. the output of the preprocessing stage is deleted as well • This method improves upon traditional implementation models in at least two ways. Scenario 2: Advanced Analytics in the Cloud The cloud is a much more cost‐effective method for delivering the kind of advanced analytics described earlier. In theory. you could do this with a set of dedicated physical servers by running different virtual machines at each step of the workflow. There is no need to purchase peak‐load storage. once the data has gone through the pre‐processing stage. it might make sense to instantiate 10 virtual servers for ETL operations that run in parallel—as the ETL operations execute. Scenario 1: Tutorial Videos in the Cloud The tutorial video service is a new customer‐facing service that could have wide‐ranging demand patterns. systems administrators can focus on immediate demand and server allocation to efficiently and cost effectively meet that demands. Deploying to the cloud is relatively straight forward and includes: • • Creating virtual images with the required software. for example. which is taken as input to pre‐processing scripts that output data into the proper format for the data mining application Allocate storage to store the raw and processed data. First. Both of the example scenarios would benefit from deployment on the cloud. the systems administrators will add virtual servers as needed. if demand warrants additional or fewer servers. As the project moves from the beta testing stage to full production. and to pay for only what is used. for as long as they need them. however. so purchasing dedicated hardware is not cost effective.The Definitive Guide to Cloud Computing Dan Sullivan New Services Under the Cloud Computing Model The cloud computing model provides a flexible infrastructure that allows service providers to acquire the compute and storage resources they need. the systems architects decide to allocate two virtual servers for the beta‐test period. once the predictive models are built.
The many critical business services are running today on dedicated infrastructure. The traditional model of service allocation has worked well for us. Next. Cloud computing models improve on the traditional deployment model by allowing you to easily share compute and storage resources and allocate only what is needed when it is needed. servers can be allocated to do task as long as needed and released at which point other servers are instantiated for the next step in the workflows. 50 .The Definitive Guide to Cloud Computing Dan Sullivan Figure 3. cloud computing can offer significant advantages. As these two scenarios show.6: In the cloud. we will identify the advantages alluded to in the scenarios just described. This approach reduces the need for ad hoc solutions to mitigating risk. Advantages of Doing Business with Cloud Computing The advantages of deploying services with cloud computing infrastructure fall into four categories: • • • • Time to deploy new services Cost control Ability to scale to demand Adaptability of resources Each of these advantages is closely tied to the architecture of cloud computing combined with management practices for allocating the costs of compute and storage services. like adding an arbitrary percentage to a project budget in case additional hardware is needed. Service providers only pay for when they are using compute and storage resources. even with diverse types of projects targeted to different users with different compute and storage requirements.
and in some cases. there is less need to analyze projected demand. storage arrays. the next stage of deployment begins. like backup schedules and patch management systems. would‐be service providers may be able to squeeze in some applications on underutilized servers. The integrity of infrastructure depends on keeping hardware and software in accordance with policies. The likely success of this approach depends on the availability of server or storage capacity and the ability to find that excess capacity. Some of the most frustrating delays come when a single piece of hardware. and deciding how many instances to start. Fortunately. It needs to be configured according to organizational standards and incorporated into support systems. or waiting for IT support to get around to installing your hardware. There are no hardware orders. If one has to cross organizational boundaries to find these resources.The Definitive Guide to Cloud Computing Dan Sullivan Time to Deploy Services When hardware is dedicated to specific functions. With the ability to rapidly adjust the number of instances. Capital expenditures for multiple servers. Procuring hardware can be time consuming. like running a fibre to the new server. it can be difficult to find compute and storage resources for a new initiative. such as a storage controller. If successful. In terms of frustration. provisioning becomes a matter of instantiating a virtual machine instance. Many of these configuration tasks are unavoidable. Delivery of hardware can take weeks. The new bottlenecks to deployment are establishing a charge account for the cost of cloud services. these stop‐gap measures will eventually have to be replaced with a more permanent solution. Once the hardware arrives. and other equipment can require multiple levels of approval. the chances of securing them can drop significantly. selecting a virtual image to run. Installing hardware is a multifaceted process. Plans may have to be reviewed and approved from both a budget and technical perspective. In the cloud model. delivery delays. cloud computing provides a framework that preserves the integrity of infrastructure without many of the time delays (and frustrations) encountered in traditional IT deployment models. In the early stages for development. months. 51 . order glitches are second only to having to wait for a simple task. Inefficient and time‐consuming efforts to find existing servers with spare cycles are also eliminated. Hardware resources are centrally managed and allocated on demand. has to be ordered separately and installed when the server arrives. to get to the front of the service queue.
they have effectively escaped the challenge of needing to constantly dedicate resource for peak demands.000 and $15. With cloud computing. you add more servers. Figure 3. you have to decide whether you want to run the $0. any cost savings on software licensing will depend on vendors adapting their pricing models to the cloud. There is also a potential for cost savings with software licensing. and that is tightly linked to the ability to scale to demand. If you make a mistake and underestimate your need. 52 . When utilization reports show that the virtual servers you have allocated are underutilized. This comes from the ability to make fairly fine‐grained decisions about resources. Systems administrators and service managers have greater control over the allocation of resources in the cloud and therefore can provision as needed for current demand.000 server under a more traditional deployment scheme. software is often licensed to named users or for a specific number of concurrent users. such as charging by the hour. You are not committed to using these servers for 2 to 3 years either. The cloud opens the opportunity for new software pricing models. Cloud servers incur costs for actual use over time. in the cloud. Traditionally. you scale back the number of servers you are running. in the cloud realm.50/hr server or the $0. Whereas you might have to decide between purchasing a $10.90/hr server. you could be charged by the hour.7: Dedicated servers incur high initial cost inline with anticipated peak demand.The Definitive Guide to Cloud Computing Dan Sullivan Cost Control and Ability to Scale to Demand Another advantage of using cloud as a delivery platform is greater cost control. Ultimately.
Cloud computing has moved this trend to the next stage with the ability to rapidly switch virtual machine images running on a hardware platform. A set of servers that were tasked with generating reports for a data warehouse might be used to generate customer invoices after that. such as OS/360 for the mainframe or RSTS for the mini‐computer. The shifts in capital expenditures occur for three reasons: • • • Reduced need for initial capital outlay Reduced need for building for peak capacity More efficient utilization through virtualization 53 . business services can be launched without the same type of capital outlays required in traditional IT deployment models. The advantages of cloud computing stem from the ability to deploy new services faster than possible under more traditional models. if you purchased a mainframe or mini‐computer from IBM. it was not uncommon to run different OSs on the same type of hardware. with Microsoft providing the dominant OS for the IBM PC while Apple introduced its OS to run on Motorola hardware. Each machine was used for different purposes. The same resource that runs an instance of Windows Server 2008 an hour ago may be running Ubuntu Linux now. the ability to control costs at a much fine‐ grained level of detail than possible before. Lowering Capital Costs with Cloud Computing With cloud computing. In the 1990s. or one of the few other hardware vendors of the day. In the cloud. The movement away from dedicated servers for single tasks to using cloud resources brings with it several sources of ROI. including the ability to rapidly scale to needs and the adaptability of resources to different tasks. you would get "the" operating system (OS) for that machine.The Definitive Guide to Cloud Computing Dan Sullivan Adaptability of Resources Through the course of IT's history. Removing restrictions on the type of software and radically reducing the time and expertise required to change OS platforms significantly improves the adaptability of hardware. By the 1980s. Digital Equipment. in the 1960s and 1970s. there has been a trend toward making computing resources more adaptable. Source of ROI in the Cloud The ROI of cloud computing is realized in two forms: reduced capital expenditures and improved operational costs. hardware resources are not tightly coupled to any single platform. hardware and operating vendors started to separate. such as batch processing business applications or interactive scientific programs. For example.
Another advantage from a capital cost perspective is that you do not have to invest for peak capacity. These savings are particularly important in larger cloud installations. Of course. one of the objectives of managing a cloud service is to have enough physical servers to meet demand but not so many that overall utilization rates drop. Traditionally. however. this means procuring dedicated servers right from the start even if the full capacity of the server is not needed for some time.The Definitive Guide to Cloud Computing Dan Sullivan As we saw in earlier. 54 . A server dedicated to the advanced analytics application would sit idle most of the month. not the peak capacity costs. The utilization of a physical server is no longer tied to a single application's usage pattern. providing for substantial savings in capital costs. the same server in a cloud configuration could have multiple virtual machines running on the physical server constantly if there is sufficient demand. but even more substantial benefit can be accrued by lowering operational costs. For example. your costs over time are more closely aligned with the average cost of delivering a service. just getting a new business service started requires access to hardware and software. especially when peak demand is highly skewed relative to other demand periods. The capital that went into purchasing a server could have been invested in a resource that begins producing an ROI right from the start instead of having to wait months before the service requires the extra initial capacity. With the cloud model. Tying up working capital in hardware brings with it opportunity costs. in the case of the advanced analytics application. Part of the ROI realized with cloud computing can be traced to the reduced cost of capital expenditures. Another source of ROI is due to virtualization. The savings can be significant. there was relatively modest average demand for computing resources but substantial peak demand. Lowering Operational Costs with Cloud Computing The most important drivers in ROI relative to operational costs can be grouped into four areas: • • • • On‐demand provisioning Reduced marginal cost of systems administration Standardization and automation Service management reporting The ROI in operational costs are subject to the economies of scale.
such as backups Coordinating with other users on the shared hosts to avoid common peak demand periods—for example. The amount of support that is needed for provisioning servers can vary significantly.The Definitive Guide to Cloud Computing Dan Sullivan On‐Demand Provisioning IT support services are necessary in any deployment model. traditional or cloud. This is a typical scenario in IT. The complexity of IT systems demands a pool of specialized IT knowledge. Figure 3. Consider the steps involved in provisioning a virtual server in a traditional IT environment (the "to do" list is even longer when dealing with physical servers). The process can be time consuming because there is a division of labor that separates those who know what has to be implemented from those who know how to implement what is needed. though. running a full backup on one virtual machine instance while an I/O intensive job is running on another instance. Service developers and business users require their talents to deploy new services and that creates a potential bottleneck.8: Selfprovisioning allows cloud consumers to allocate and manage their own resources. 55 . Cloud computing avoids this problem with support for self‐provisioning. which includes: • • • • • Submitting a service desk ticket requesting a virtual machine instance Identifying which physical server will host the virtual machine Determining the configuration parameters for the new instance Specifying required support services.
A typical list of systems administration tasks include: • • • • • • Installing new applications and packages on servers Patching OSs and applications on each server Backing up local storage on each server Allocating space to file systems as needed Reviewing and purging log files Performing security checks. cloud infrastructure abstracts implementation details such as allocating memory or CPUs to particular virtual machine instances. systems managers have to repeat these tasks for each server. Reducing Marginal Costs of Systems Administration To understand how a cloud infrastructure can result in significant ROI. so does the chance of human error during systems management operations. cloud consumers have access to management systems that allow them to specify the type and number of virtual instances to create. 56 . you only need to look at how systems administration changes with the cloud. details about what device drivers have to be installed or which libraries are needed to run an application have already been addressed when the virtual images were created. Also. Fortunately. All the hardware in the cloud is managed centrally and virtual machine images are maintained in a service catalog. such as running vulnerability scanners and reviewing results for each server In conventional environments.The Definitive Guide to Cloud Computing Dan Sullivan With a self‐provisioning system. however. Consistency across servers is important to reduce the amount of time required to maintain systems. but they can still be time consuming. For instance. service management tools support these efforts. so cloud consumers do not have to deal with low‐level details. as the number of servers grows.
The Definitive Guide to Cloud Computing Dan Sullivan Figure 3. The service catalog is the set of images available for running in the cloud. there may be several Windows server and Linux images that have been configured for general use. Consider a simple example. There may also be more specialized images for relational databases or content management systems.9: Cloud systems administration entails maintaining images in the service catalog. In the cloud. maintaining individual servers is swapped for maintaining virtual machine images in the service catalog. which is linked to each physical server. Having a centralized repository of virtual machine images can significantly reduce the time required to perform routine tasks. unlike traditional systems administration. 57 . For example. Still other images may be designed for developers who need to routinely instantiate application servers for development and testing as well as for production use.
systems administrators will have to verify the success of the patch in each case. you do not have to worry about storage services. a new patched version is generated and uploaded into the catalog. The service catalog image is patched. but there may be instances of the unpatched image running in the cloud. Much of the tedium of setting up monitoring processes to collect performance and usage data is also automated with service management systems. and the tradeoffs between the different kinds of file systems. Images are deployed and virtual machine instances are started using a management console. Systems administration in the cloud may be less labor intensive but sometimes difficult decisions about balancing security or stability with business expectations remain. Now compare that with patching a service catalog. The images in the service catalog are configured to work with cloud storage services. they are provided for you. These are not particularly difficult tasks. Standardization also enables behind‐the‐scenes automation that further reduces the demand for systems administrator expertise. If a critical security patch is released and has to be applied to 50 servers.The Definitive Guide to Cloud Computing Dan Sullivan A midsize business could easily run 200 servers with a mix of OSs and applications. This example does raise another difference from a systems management perspective. The existing image is removed from the catalog. systems administrators will have to apply each patch manually. how much space to allocate to each. so a cloud user who knows how to deploy a Windows server knows how to deploy a Linux server or a relational database as well. you reduce the overhead in maintaining them. when you install Linux on a server. the patch has to be applied 50 times. but you do need to know something about how partitions are used. The last issue is a question of policy analogous to deciding when to schedule a critical patch for a server. 58 . Where are those images? How long will they continue to run? At what point should the instances be shut down and restarted using the patched version? The first two questions can be addressed using cloud management software. Even with patch management applications to help. For example. Standardization and Automation Another reason for operations‐related ROI is that by standardizing on a set of general purpose virtual machine images. In cases where automated tools are not available. What could have taken 50 distinct tasks is done in one step. When you instantiate servers in the cloud. you have to decide what type of file system to use and how to partition the disk.
however. for new service deployment when using the cloud.The Definitive Guide to Cloud Computing Dan Sullivan Service Management Reporting ROI is not just about technology but about how you manage it. servers can be powered down to save on energy costs. comes from reduced operational labor costs enabled by self‐service management. consider several cloud metrics as well as the source of ROI for your particular business. Systems management hours. Some of the measurements service providers might use include: • • • • • • Number of server hours allocated Overall average server utilization Average server utilization by hour Average server utilization by instance type Total storage space used Amount of network I/O Data on these measurements can help determine how many servers to allocate and how long to run them. especially if there are charges based on network traffic. Data on storage use and the amount of network I/O can help guide optimization of application performance. if not eliminated. such as economies of scale that will benefit larger businesses than smaller ones. The big savings. If resources are underutilized. as well as factors you can manage. IT may also want to promote the use of the cloud and publicize availability of resources. and standardization. such as server utilization rates. Labor can account for significant portions of IT operating budgets but should be significantly less for cloud services. This is especially important when using a private or hybrid cloud model. To assess the value of cloud services to a business. Much will depend on factors out of your control. Key metrics for these clouds are: • Utilization of all cloud resources. service providers can better understand the resources they use and adjust their allocations accordingly. Assessing the Business Value of Cloud Services The ROI in cloud technologies will vary from one business to another. Capital expenditures are significantly lower. • 59 . With service management reporting. The reason to track particular metrics in cloud computing is no different than that of any other business operation: to quantify the costs and benefits of the service. automation. Many aspects of cloud computing contribute to the ROI in the technology.
These are sometimes necessary to meet business requirements. and the adaptability of resources. in turn. and reduced energy costs Lower software costs because software licensed per server can have improved utilization that parallels hardware utilization Self‐service management. different types of business applications can benefit from deploying in the cloud. Further benefits of cloud computing accrue with regards to reducing the time to deploy new services. Servers in the cloud can be repurposed rapidly and with minimal technical expertise. reducing the need for dedicated servers and their typical low utilization rates. such as adding contingency funds to a project budget to purchase additional hardware to meet unexpected demand. they may be incurring more costs than they recoup through usage charges. Time to provision. If a sufficient number of servers are not available.The Definitive Guide to Cloud Computing • Dan Sullivan Virtual machine image use. Infrequent use or use by only one user can also indicate specialized or "one off" images. Summary Cloud computing offers new ways to deliver business services. The ability to scale compute and storage resources as needed reduces the need to build for peak demand. more ways to control costs. These include the ROI realized from: • Improved hardware utilization. • In addition to these more global metrics. reduces the cost of delivering services while avoiding costly risk mitigation strategies. looking at ROI based on specific elements of cloud infrastructure is useful as well. This metric can indicate insufficient resources in the cloud. lower maintenance costs. the cost of maintaining them will increase. This. but if the number of specialized images grows. which reduces systems administration Increased productivity due to reduced wait time to deploy servers and applications • • • Cloud computing is an evolution in information technology and so it is not surprising that many of the same metrics and ROI factors we have used in IT for years have analogs in cloud computing as well. 60 . or used infrequently. As the two example scenarios highlighted. especially when fewer servers are required to meet a workload leading to reduced capital costs. All images in a service catalog have to be maintained. If some images are not used. Charges may need to be adjusted to recoup the full costs of maintaining specialized images. users will have to wait for other jobs to finish in the cloud before there virtual machine instances will be provisioned.
In the next chapter. Even more substantial savings can realized with self‐service management and savings in systems management. automation. cloud users can not only deploy services in the cloud but also manage them effectively. 61 . examined some of the technical aspects. and service management reporting. The first three chapters have introduced cloud computing. we will turn our attention to the question of how to begin planning for cloud services in your business. Capital costs are reduced largely due to higher utilization rates of servers. With standardized images. and described in general how cloud computing can improve service delivery.The Definitive Guide to Cloud Computing Dan Sullivan Perhaps the primary driver for the adoption of cloud computing is the ROI.
In particular. move on to looking at the current state of IT infrastructure. but its application to real‐ world business problems requires the examination of organizational issues that range from bordering on the technical to being the provenance of business executives responsible for overall strategy. this chapter considers the following: • • • • How cloud computing can help your business Assessing current capabilities Introducing cloud computing as a new model for consumption and delivery Measuring the value of a cloud The discussion will start by identifying key business priorities. as you must have a clear idea of what cloud computing offers from a technical perspective before you can appreciate what it can do for you from a business perspective. Figure 4. Cloud computing has and always will be a rich technical area. the business drivers determine how cloud computing is applied. virtualization.1: The technical aspects of cloud computing shape what can be done from a business perspective. 62 . Much of the coverage of cloud computing has focused on the technical aspects of this computing model: the consolidation of servers. This is understandable.The Definitive Guide to Cloud Computing Dan Sullivan Chapter 4: How Cloud Computing Will Help Your Business Cloud computing changes the way we do business. security. and so on. and procedures. services. and finally assess the financial value of a cloud to the organization. This chapter turns attention to the business side of cloud computing. describe how to transition those capabilities to a cloud‐enabled enterprise.
Before proceeding to consider priorities. Reality Consider a healthcare provider with several hospitals. there is some allure to being on the cutting edge and having the latest technology. Moving your business to the cloud should begin with considerations that have nothing to do with clouds. and hundreds of doctors serving thousands of patients. the first question to ask: What is the problem? To get to the answer to that question. The executives believe. Certainly. delay. and barriers to innovation. No rational business person would make such a fundamental change to core infrastructure without understanding the consequences for the businesses. but chasing technology trends for their own sake is not a sound strategy for long‐term business success. why change? Why bring on the risks associated with a new technology. at least not yet. executives at the healthcare provider decide to disseminate information on patient conditions. Cloud computing is a solution. with sufficient feedback on the results of treatment choices along with details on the cases where particular treatments work and do not work. After all.The Definitive Guide to Cloud Computing Dan Sullivan How Cloud Computing Can Help Your Business Adopting cloud computing is a major change from the traditional distributed systems models many of us use today. physicians will be able to reduce uncertainty associated with selecting treatment options. treatments. the healthcare provider will have to: • • • • • Create a consolidated reporting system such as a data warehouse Develop procedures for extracting and loading data from multiple sites into the data warehouse Create a reporting infrastructure to deliver information to physicians in a way that is easy to use and fits with their work patterns Establish governance over the data warehouse and reporting procedures to ensure compliance with HIPAA and any other relevant regulations Define a mechanism to collect feedback from users to improve the system 63 . and outcomes. inefficiencies. if your current computing and storage systems are meeting your needs. you need to: • • • Identify business priorities Identify operation inefficiency Identify barriers to innovation These steps help you identify what the business is striving to achieve and what is hindering those efforts. tens of clinics. As part of a strategic plan to improve the quality of services while controlling costs. let's consider a hypothetical scenario that highlights the issues relevant to aligning business goals and technology infrastructure. Only after you understand that can you turn your attention to addressing the problems that thwart. Business and Technology Alignments: The Ideal vs. and increase the cost of your business operations. Instead. technology is adopted in service to a business strategy. To implement this plan.
(There is plenty of storage on another department's disk array. but organizational boundaries rule out using it. this is a fantasy. Here is a version of the scenario that might ring true for more readers. The support services group within IT is already familiar with these standardized tools. so there is minimal marginal cost to support another set of users. but the list is sufficient to demonstrate the potential drag that IT operations can have on business initiatives. the reality that many of us have experienced in projects like this is far different from this scenario. and reporting tools. To many. The requirements for the reporting project outstrip the available budget. Fortunately. IT has standardized on a relational database. Several reporting tools are used in other business intelligence projects. reporting. 64 . First. standardized applications. Rack space and cabling are a problem that can be worked out with the infrastructure management group. the next step is to determine how the IT department will proceed to implement the plan. This ideal scenario is one in which infrastructure. so access controls can be readily established and managed. will be in a few weeks. so an internal evaluation will be done to determine the best tool for this effort. The company has a site license for the database software but this project requires several additional packages that will have to be purchased.The Definitive Guide to Cloud Computing Dan Sullivan With the high‐level requirements in place. though. Requirements will have to be prioritized and some features will have to be delayed until later phases. Development work can begin immediately. Some of the issues that would likely arise include: • • • • • • • Acquiring servers and storage to house the data warehouse Purchasing licenses for database.) Hardware will have to be procured and installed. These applications already work with the identity management system in place at the organization. and load (ETL) tools Assembling a team to install and configure the infrastructure once it is acquired Designing logical and physical data models for the data warehouse Developing reports Establishing access controls over reports and data Creating a support team to monitor data warehouse processes and provide end user support There are other items you could add to the list. a data warehousing methodology. given their backlog. let's depict an ideal scenario. and support services are in place and readily available for new initiatives. which. transformation. IT has sufficient server and storage capacity for the data warehouse. and extraction. There is insufficient storage available to the business department that owns this project.
and tax support staff with inefficient deployments. In this scenario.2: Innovative IT projects require an array of technology and services that can be difficult to coordinate and integrate.The Definitive Guide to Cloud Computing Dan Sullivan Figure 4. allocated resource across organizational lines. the needs of the business for rapidly deploying an important medical decision support tool is hampered by the way budget for projects. delays. The collective effect of seemingly small and. That is a short way of saying IT services support business objectives in a straightforward manner and do not introduce unnecessary cost. or other burdens on a business strategy. 65 . in many cases. failure to standardized as much as possible on software. expected problems is to slow down and prolong the implementation. Identify Business Priorities One of the most important aspects of successful IT services is that they align with business goals.
to detect early warning signs of churn. if you start with business priorities. 66 . knowing your business priorities may lead to the conclusion that cloud computing is not something you need at the moment. Operational inefficiencies. if cost control is a top priority. Operational inefficiencies in the IT realm come from the way we deploy and utilize hardware and the way we manage software. the business loses productivity. Of course. cloud computing is not a panacea that will solve all your problems. Low server utilization is a common inefficiency. This approach minimized problems with conflicting requirements and allowed administrators to manage servers and applications as a tightly coupled unit. It may be an appealing option at a later time. increasing server utilization through virtualization and increasing storage utilization through consolidation with cloud computing architectures can help. but your business may not be in a position to move to the cloud until it improves its IT governance practices. many organizations used a "one application. ironically.The Definitive Guide to Cloud Computing Dan Sullivan Although there is no set of priorities that would apply to all or even most companies. Prior to the widespread adoption of virtualization. you may need to invest in advanced analytics. Identify Operational Inefficiencies Operational inefficiencies are a drain on the bottom line. common priorities include: • • • • • • Controlling costs Expanding market share in mature industries Expanding into new markets in growth industries Improving customer service Improving customer retention Increasing cross selling Whatever the priorities and their relative importance. Caution To be clear. for example. the business is realizing an opportunity cost as well as incurring unnecessary energy costs. Knowing these will help determine whether and how cloud computing can help your business. The price we paid for this was wasted CPU cycles. If improving customer retention is important. When an employee has to perform ten steps to complete a task that could be done in six steps. one server" approach to deployment. it is critical to identify these for a business. Whatever your conclusion. such as data mining and statistical analysis. There are times when cloud computing is not the right solution. For example. Advanced analytics can be compute‐intensive and is a good application for cloud computing. are often found in IT departments that have traditionally been a source of increased productivity. When servers are powered on and functioning but not running productive jobs. you will at least justify why or why not to pursue cloud computing or any other technology.
As a result. Figure 4. the problem arose from the constraints on procuring new hardware. Configurations could be tailored to individual applications. configuring software.The Definitive Guide to Cloud Computing Dan Sullivan Less obvious was the management inefficiencies that came with the one application. with different applications and services and all requiring slightly different support. and ordering a sequence of deployment events that account for a range of dependencies between steps. Identify Barriers to Innovation The scenario described earlier shows how innovation can stagnate because of technology barriers. 67 .3: Standardizing server configurations is one way to reduce systems management inefficiencies. the number of servers a single administrator could manage was limited. Had a standard configuration been developed for a limited set of roles. and this would result in more productive systems management. so an IT group could soon find that many of its servers had different operating system (OS) components installed. It is important to note that the barriers in that scenario were not caused by poor management or unskilled IT professionals. systems administrators would have less variation to contend with. one server model.
pinpoint operational inefficiencies. These three elements comprise the key business drivers that can guide the successful use of cloud computing in your organization. Cloud computing is an evolutionary advance in computer architecture and service management. businesses have access to a wider pool of suppliers and business partners. it helps to have a clear understanding of current technical capabilities. and the list of potential competitors is more likely to grow than not. 68 . Assessing Current Capabilities Technology capabilities are a combination of hardware and software infrastructure within an organization as well as the management practices that govern the use of that technology. and systems administration practices are as relevant to delivering services through a cloud as they are to other delivery methods. and you see that barriers to innovation can be a potential long‐term drag on the company overall. and identify barriers to innovation. As noted earlier in this chapter. Add to this list the demands on companies to consistently meet performance expectations quarter after quarter. Sound management practices. and coordinate multiple software components Any or all of these can be significant barriers to innovation. software development life cycle methodologies. In the time of a globalized economy. customers have more options than ever before.The Definitive Guide to Cloud Computing Dan Sullivan The scenario can help you see the different types of barriers to innovation that can creep into IT operations: • • • • • Delays in procuring and deploying hardware Initial capital costs Ongoing operational costs Insufficient support staff The need to evaluate. it improves on what came before it but does not represent a wholesale replacement. but before adapting new technologies. For the purposes of understanding the role of cloud computing in improving business services. The first steps to understanding how cloud computing can help your business is to formulate a clear picture of business priorities. select. let's consider several types of capabilities: • • • • • Infrastructure Platforms Applications Governance Management and reporting It is important to have a clear and comprehensive understanding of these capabilities because they are all relevant to adopting the cloud computing model. business requirements drive technology‐based solutions.
and relatively low performance.The Definitive Guide to Cloud Computing Dan Sullivan Infrastructure Capabilities IT infrastructure for the purpose of this discussion includes server and storage hardware as well as networking components. If your operations are similar to most. not average. There may also be an opportunity to consolidate data centers or at least servers currently located in remote offices. 69 . Such consolidation can have an immediate impact on the power and cooling costs of a data center. of course. a move to cloud computing is an opportunity to consolidate servers and decommission those with high maintenance costs. and those servers were configured to handle peak. so such hardware are ideal candidates for hosting Windows and Linux platforms. Cloud infrastructure can be built using low‐cost commodity hardware. content management servers. databases. and directory services. you will have many servers running single applications. Unix and mainframe OSs are typically found on enterprise‐scale computers running high‐volume. you should have a clear idea of overall server utilization. capacity. Enterprises typically have a number of platforms: • • • • Windows Linux Unix Mainframe OSs Windows and Linux often run on servers that provide specialized functions. Platform Capabilities Platforms are the OSs and application stacks that run on a company's IT infrastructure. no standard configurations. When assessing current capabilities with regards to infrastructure. If this is the case. mission‐critical applications. Unix OSs run on these servers as well. Reducing the number of sites can help ease management overhead and streamline IT operations such as backups. consider: • • • • • The inventory of servers currently in place The geographic location of servers The costs of maintaining each server Utilization metrics for servers Network infrastructure between sites At the end of the infrastructure assessment. such as email servers.
but you might find you can use fewer different distributions than you currently have. 70 . you will want to ensure that all application stacks currently in use and needed in the future are supported in the cloud. OS Consolidation Standardizing on a reduced number of platforms will reduce systems management tasks and provide a step toward the type of self‐service management that is such an important factor in cloud computing's ROI. It may not be possible to find a Linux distribution that is optimal for all needs. Application Stacks Application stacks are middleware that reduces dependencies between applications and OSs. consider reducing that number. though.Net LAMP (Linux/Apache/MySQL/Perl or Python) J2EE (Java 2 Enterprise Edition) Application stacks are chosen for their fit with system requirements and the skills of developers working on the applications. so there is probably less opportunity to consolidate at this platform level.The Definitive Guide to Cloud Computing For the purposes of assessment. Common application stacks are: • • • Microsoft . For example. this is a good time to move those applications to Windows Server 2008. Standardizing in this case does not mean committing to using only Windows or only Linux but to reducing the amount of variation in the platforms. Similarly. like different versions of Unix. They will be just as important in a cloud environment as they are in today's distributed system environments. Application stacks and middleware abstract low‐level OS details and provide a consistent programmatic interface and set of services. you should collect information about: • • • The number and version of Windows OSs The number. version. if a department is still running an instance of Windows Server 2000. they can be difficult to port. can harbor enough differences to make porting software difficult. When applications are written directly to an OS. Just as important. Even similar OSs. Moving applications from one stack to another can be a considerable undertaking. and distribution of Linux OSs The application stacks that run on these OSs Dan Sullivan The goal here is once again to consolidate as much as possible. if several distributions of Linux are currently supported.
The Definitive Guide to Cloud Computing Dan Sullivan Microsoft .NET Framework is designed to leverage SQL Server database and other OLE/ODBC data sources.NET Framework is a development framework for building Web applications for Microsoft platforms. Perl. LAMP (Linux/Apache/MySQL/Perl or Python) LAMP is a set of commonly used open source systems for building Web applications. as well as dynamic languages such as IronRuby and IronPython Windows Presentation Foundation. a user interface (UI) framework Silverlight.NET. The framework includes several components: • • • • • • • • A common language runtime that acts as an abstraction layer above OS functions Base class libraries Support for both compiled languages. such as Visual Basic and Visual C#. a set of data access services Windows Workflow Foundation Not surprisingly. the individual components of this set of platform tools had long and well‐developed histories prior to the advent of LAMP. Unlike the Microsoft .NET Framework. the . Each of the four components provides a basic service commonly needed in Web applications: • • • • Linux is the OS underlying the LAMP stack Apache is the Web server and related modules that may be installed as needed for particular applications MySQL is a popular open source database suitable for a range of applications sizes and needs PHP.NET tools for building rich Internet applications (RIAs) Windows Communication Foundation (WCF) for service‐oriented architectures ADO.NET Framework Microsoft . and Python are scripting languages used to implement custom application functions 71 . a set of .
The Definitive Guide to Cloud Computing Dan Sullivan Figure 4. a distributed object container Java Transactions API Java Messaging Service API Java EE Connector Architecture Java XML Streams Java Persistence API Java Server Faces.4: The LAMP stack consists of a small number of independently developed open source components that are commonly used together for Web application development. such as portals and content management systems. is a middleware framework designed for deploying distributed Java applications. there are multiple components providing a range of services for application developers. a UI framework These components are bundled together and incorporated into Java application servers. sometimes referred to as J2EE. Java Platform Enterprise Edition The Java Platform Enterprise Edition. Like the Microsoft . 72 .NET Framework. These include: • • • • • • • Enterprise JavaBeans. The application servers sometimes run higher‐level additional application development components.
The goal of assessing application capabilities is to determine: • • • • The relative priority of moving an application to the cloud The difficulty to move the application to the cloud Changes to application management practices that may be needed after the move to the cloud Potential risks and mitigating strategies When it comes to prioritizing moving applications to the cloud. you want to avoid immediately moving applications to the cloud that may have special requirements. As even this simple scenario shows. high‐security applications that would require any deleted data be not only deleted but overwritten multiple times to reduce the risk of unauthorized reconstruction of that data. they provide many of the same functions but do so with fundamentally different tool sets. this assumes that jobs can be scheduled together that require the same platform. as departments will likely be billed for the time virtual machine instances are running. When assessing existing capabilities. it is important to catalog all the platforms and main platform components used so that they can be supported in the cloud as well. they can once security procedures are in place to meet the application requirements. Running applications in the cloud and on a dedicated server will require different management routines. At the same time.) It is not the case that these applications can never be moved to the cloud. the way you manage cloud applications will have to account for new billing structures and server use patterns. Of course. For example. Billing rules should also be considered when scheduling jobs. or (c) have peak demands that could take advantage of elastic allocation of CPU and storage capacity of the cloud. you should look for those systems that are (a) under‐utilizing the servers they run on. Also. (Deleting data can be done by marking a data block as available for use. so old data can continue to reside on the disk even after files have been logically deleted. they will want to optimize their workflows to keep the virtual servers utilized as much as possible when they are running. it would be best to schedule jobs continuously rather than shutting down and restarting. if a department is charged for a full hour of virtual server time regardless of how much of that hour is utilized. a cloud storage provider may provide sufficient redundancy in data duplication that you may reduce the number of backups performed. 73 . Application Capabilities Enterprises run a wide range of applications and many of these are suitable for running in the cloud. (b) are running below needed performance levels because the hardware does not adequately serve current loads. For example.The Definitive Guide to Cloud Computing Dan Sullivan As you can see from the descriptions of three common application platforms. For example.
the cloud changes the way you deliver services and provides new opportunities to change management or governance policies. ensuring security and compliance standards can be met Being able to run applications on a standardized platform that may require specialized runtime libraries or utilities Having access to virtual machine images that support the application. The goal of the governance capability assessment is to understand the mechanisms that are already in place to guide IT operations. Poor governance affects all users of the cloud. Governance of cloud operations is required for all types of clouds: private. they will include: • • • • • Complying with government and industry regulations Defining and enforcing audit controls and security procedures Establishing cost allocation and cost recovery policies Setting policies on the management of the service catalog Adjusting existing policies to accommodate cloud services These governance requirements should not be new with cloud computing. As noted earlier. Cloud computing will not improve governance practices. These risks include: • • • If using a public cloud provider. the governance practices for clouds are a potential single source of failure.The Definitive Guide to Cloud Computing Dan Sullivan Another area you need to consider during the application assessment is the risk of moving applications to the cloud. These considerations with regard to applications represent just some of the broader issues that must be addressed as part of governance processes. public. and make necessary changes. change control policies may become more flexible with regards to platform‐level changes because multiple versions can coexist in the service catalog. but in general. 74 . For example. and hybrid. identify weaknesses. though. The need for governance is independent of IT architecture choices. but it still must be considered at the level of application requirements. this can be an issue if a cloud provider only offers the latest patch version of an OS and the application does not run correctly under that particular version Moving applications to the cloud entails sharing control with the cloud provider. This may be less of an issue when using a private cloud. Governance Capabilities A capabilities assessment should include an assessment of governance practices as well. The policies that are implemented will vary by type of cloud. but poor governance can eventually undermine the value of the investment in cloud computing. Although cloud architectures are fault tolerant and resilient.
platforms. When a private cloud is used. applications.The Definitive Guide to Cloud Computing Dan Sullivan Management and Reporting Capabilities With cloud computing. Reports and data on cloud usage should be available for both front‐line managers responsible for scheduling jobs and budgeting for services and for back‐office billing operations. service consumers have greater control over how they use computing and storage resources. Management reports are the key to delivering that information.5: Organizational capabilities in the form of infrastructure. To optimize their use of these resources. they need information about their workloads. and other metrics. costs. Front‐line managers should have access to near real‐time billing information on CPU utilization and storage allocations so that they can tune workflows. Existing financial reports would then provide an additional set of reports for front‐line managers. Figure 4. They should also have comparative historical data so that they can detect trends and properly plan for future needs. back‐office billing systems will need to accommodate billing or charge backs for cloud services. 75 . and reporting enable the deployment and use of cloud computing services. governance and management. levels of utilization.
but we will briefly address the use of public clouds. Introducing Private Cloud Consumption Model There is nothing inherent in cloud computing that requires the cloud be owned and operated by another business. specialized workflows. It is also a viable option for meeting peak demands of jobs that are readily moved to a public cloud.The Definitive Guide to Cloud Computing Dan Sullivan An assessment of organizational capabilities. Introducing a New Model for Consumption and Delivery Introducing cloud computing can be done in two ways: by using a public cloud or by using a private cloud. The infrastructure and services are managed by the provider and used by service consumers. but it would take significantly more planning. and reporting procedures will provide an organization with a starting point for introducing cloud computing services. a department‐level manager could: • • • • • • Establish an account with a public cloud provider Upload data for analysis into the public cloud provider's storage system Select from the public provider's catalog of OSs and other platform software Allocate the necessary number and types of servers Run the job Shut down the servers. collect the results. tactical use can also be done in cases where confidential data. 76 . spanning existing infrastructure. specialized workflows. Cloud computing is an architecture and a set of services that enable access resources on demand. Public clouds allow consumers to experiment with the cloud delivery model without fully committing hardware. or complex security requirements. or complex security requirements exist. platform. The provider can be a third party offering a service to the public or an IT division within a company offering computing and storage services to other departments within the company. experimental evaluations that do not involve confidential data. In a very short time. software. We will focus most of our attention on the latter. applications. and complete the task This type of isolated. governance and management. Introducing Public Cloud Consumption Model Public clouds can be introduced quickly for small. and management to a full‐scale deployment. along the lines of what we will be describing shortly in the discussion of a private cloud deployment. Running significant portions of your business services in the cloud for extended periods can certainly be done but will require the type of attention and planning that one finds with the use of private clouds.
these changes fall into three areas: • • • Deploying existing infrastructure in a private cloud Enabling application services in a cloud Managing a cloud Deploying Existing Infrastructure in a Private Cloud The first step is to establish the hardware infrastructure for running the cloud. If this is the case. you should expect hardware failure in architectural configuration. Actually. Some of the factors to consider when selecting hardware: • • • • • • • • Number of CPUs and cores in the server Amount and speed of RAM Network interface card throughput Cost of maintenance contracts. Management overhead could be simplified with cloud management software. The last. If the business has a large existing infrastructure with low utilization and high systems management overhead. businesses can still benefit from spending less on infrastructure than they would if they did not use a cloud‐based approach. The number of servers could be reduced because fewer will be needed to meet existing demands. older servers with lower overall performance and higher maintenance costs are obvious targets for elimination. 77 . standardization. if any Cost of leasing contracts. so you would expect to use fewer servers for the same level of demand. Existing hardware may be used for this. the company could benefit from redeploying their infrastructure to a private cloud. Introducing a private cloud will entail changing procedures and practices. it will require planning to ensure existing services are not disrupted during the transition. you reduce the need to maintain multiple types of backup components and streamline troubleshooting procedures. but of course. the economic benefit will depend on circumstances within the business providing a private cloud. By standardizing hardware. if any Power consumption Cooling requirements Standardization Most of these are common sense considerations. such as lower management costs and no need for capital expenditures. In cases where capital expenditures are required.The Definitive Guide to Cloud Computing Dan Sullivan A private cloud may appear to lack some of the economic advantages of cloud computing. This may or may not be the case with private clouds. addresses the fact that you should expect hardware failures in the cloud. One of the goals of cloud computing is to increase the server utilization. The first step is to identify the servers to use for cloud services.
If data centers are being consolidated. Also. For example. and configure and that ultimately leads to reduced support costs. Operation management software is needed to track the use of compute and storage resources in the cloud. for example. As noted earlier. and so on. throughput. the service catalog may need to include: • • • Windows Server 2008 with . this is an opportunity to standardize on software components. patch.The Definitive Guide to Cloud Computing Dan Sullivan Storage hardware should be selected for comparable reasons: speed. possibly in multiple configurations. Managing a Private Cloud Managing a private cloud requires software and procedures. They should also have the ability to: • • • • • Monitor their jobs Schedule their jobs Establish complex workflows Track storage use Create specialized virtual machine images with custom configurations 78 . The advantage of standardizing is that there are fewer pieces of software to manage. additional network capacity may be required. Enabling Application Services in the a Cloud Application services begin with a service catalog.NET Framework Windows Server 2008 with Java Enterprise Edition framework Linux with LAMP framework In addition to the applications needed in the existing configuration. cooling. power consumption. to support existing business services. there will be additional software needed to manage the cloud. one Internet access provider is down. middleware. cloud consumers should have the ability to track their use and costs as they make use of services. This is the set of all OSs. As with deploying hardware. Software services in the catalog should be based on business requirements. capacity. and applications that will run in the cloud. Network capacity and throughput should also be considered at the early deployment state. There will be needs for different OSs and application stacks. consider the levels of redundancy on the network to ensure services can continue at needed levels if.
The Definitive Guide to Cloud Computing Dan Sullivan Management tools are also needed by IT support staff to maintain the services catalog. Images will need to be patched. For example. and utilities included Patch levels Number of times instantiated Location of sources used to construct the image Many of the same service management procedures used in non‐cloud environments are still relevant to the cloud. systems administrators should be able to track metadata about every item in a service catalog. access controls will need to be applied. libraries. Figure 4. such as: • • • • • • Description of a virtual machine image Date it was created Applications. 79 . identities will need to be managed. and charges will have to be made to departments.6: Management components include the service catalog of a platforms and applications available in the cloud as well as management support software.
deploying. these costs do not go away.The Definitive Guide to Cloud Computing Dan Sullivan Measuring the Value of a Cloud Moving to a cloud computing environment will change the IT cost structure and impact both capital cost structures and operational costs. In addition to these hardware costs. and maintaining applications. The end result is less capital expenditure because of more efficient use of infrastructure. Changes to Operational Cost Cloud computing can prove advantageous for operational costs in four areas: • • • • Labor Infrastructure maintenance Facilities operations Simplified accounting Labor Costs Labor costs are reduced with the use of self‐service management enabled by cloud management software. and schedule them when needed. These are infrequent but significant costs that are budgeted outside the normal operations budget. but they are reduced. adding to the capital expenditure. 80 . there will be the cost of application and OS licenses. that is not the case for a fully functional application environment. Consumers of cloud services have the ability to choose the virtual servers they want to run. which in turn depend on access to a skilled IT professional to perform the configuration. determine what applications to run. central IT can plan for capital costs across a wide base of users. they often have to plan for capital costs. Consider the costs of developing. The production server may actually be a cluster of servers and a load balancer in order to scale to peak demand. Rather than having multiple service managers develop their own capital budgets. Changes to Capital Cost In a conventional IT model in which departments or service managers use dedicated servers. complete with wide ranging contingency funds either explicitly or implicitly added to the budget. and applications. For small projects. The load balancer will provide some degree of high availability. platforms. Although the cost of a server or two may be accommodated in an operational budget. testing. you would need development and test servers. but disaster recovery procedures dictate a backup set of servers in an offsite location. The key is to efficiently share resources rather than dedicate servers and storage arrays to single services or departments. For hardware. The standardized service catalog reduces the need for costly software configurations. In the cloud. Storage will be required as well. a single high‐ end server may serve for both as long as each ran in its own virtual environment.
which in turn reduces power and cooling costs. If there are failures (and there will be).The Definitive Guide to Cloud Computing Dan Sullivan The cloud can reduce IT support labor costs in other ways. Standardizing on infrastructure is no exception. the patch would be available to users of those images the next time they instantiate their virtual machines. For example. Inventories of spare components are kept to a minimum as well. then hundreds of servers may be involved. By driving up the average server utilization. Facilities Operations Another contributor to savings in operational costs comes in facilities management. updating and patching becomes less labor intensive. The same patch could be applied to images in the service catalog in fewer numbers because only one copy of each configuration is needed. Reporting and integration with financial systems is less complex than if a large number of specialized cases and accompanying business rules have to be accommodated. heat that has to be removed with costly cooling systems. Also. With a centralized service catalog. IT infrastructure can consume significant amounts of power leading to high energy costs. Cloud computing presents clear cost benefits in both capital and operational costs—as long as proper planning and assessment are done. This requires identifying which servers need the patch. For example. but the conversion from electricity to computation is not perfect. The inefficiencies in conversion are realized in the form of heat. reviewing the results of the patching operation. you could build pricing schedules that could account for additional costs for OS or application licenses. 81 . a virtual machine running on a dual core processor (or its functional equivalent) for 1 hour can be defined as a unit of computing resource with a standard price attached to it. deploying the patch through an automated delivery system. cost recovery is simplified. Adding new components. a gigabyte of storage stored for one day could be a unit of storage for accounting purposes. and manually applying the patch to those servers that failed to be patched correctly using the automated method. This can be a time‐consuming burden on IT support staff with other regularly scheduled tasks to complete. Infrastructure Maintenance Standardization is a well‐established method to reduce costs. From these fundamental units. Of course. the new units are readily swapped in without requiring configuration changes. Clouds run in a centralized data center. so there is less need for remote office visits to deal with failed hardware. a business can reduce the number of servers needed. Cloud consumers can readily plan their expenditures. Similarly. such as servers. Simplified Accounting One of the advantages of cloud computing is that it provides a way to standardize computing and storage units of service. to a cloud will have low marginal costs if they are configured similarly to servers already in the cloud. all that power that comes into the data center gets converted to useful computation. With this type of model. if an OS vendor releases a critical patch that has to be pushed to servers.
platforms. begin by assessing the current state of business and technical operations. To get the most of your investment. applications.The Definitive Guide to Cloud Computing Dan Sullivan Summary Cloud computing is an efficient framework for utilizing computing resources. This includes identifying business priorities. It also entails assessing the current capabilities in terms of infrastructure. enabling application services. and reporting. Deploying a cloud is a multi‐stage process that includes deploying existing infrastructure. and barriers to innovation. 82 . governance and management. and managing the cloud. operational inefficiencies. The value of the cloud will be measured in both capital and operational cost savings.
Now it is time to turn our attention to strategies for moving an organization from thinking about cloud computing to using cloud computing. and the constraints on actually delivering them. From there. we examine issues such as scalability. this generally means understanding the business drivers that dictate the services to be delivered. High‐level discussions about planning and architecture in the first two sections of this chapter are complemented by a set of use case scenarios in the third section of this chapter. the expectations for those services. offers a number of compelling benefits. we can document workloads that we expect to utilize the cloud. In the realm of IT. manageability. and service delivery in terms of design and implementation issues. This is not surprising. In the second section on architectural principles. and manageability. This chapter focuses on how to plan for the organizational and technical issues around the move to cloud computing. cloud computing is a phase in the evolution of IT services delivery. 83 . as we have seen in previous chapters.The Definitive Guide to Cloud Computing Dan Sullivan Chapter 5: Strategies for Moving to the Cloud Cloud computing is a framework for delivering services that. It is specifically structured around three broad topics: • • • Planning principles Architectural principles Use case scenarios The first section on planning principles will describe a process for understanding the current state of IT services and framing them in such a way that we can properly start delivering these services in a cloud‐based environment. The goal of the use cases is to provide concrete examples of applying the planning and architectural principles to typical scenarios facing cloud computing adopters. control. As I have noted in this book. it builds on previous practices to deliver new levels of efficiency. Many of the same rational methods and management techniques we use in IT planning and deliver today are relevant to cloud computing. Planning Principles for Moving to Cloud Computing Planning a move to cloud computing starts pretty much the same as any other planning process: understanding where you are and where you are trying to go. With a clear and well‐defined set of requirements. Each of these steps will be considered in turn. we can move to a detailed definition of requirements.
These can include: • • • • • • Increasing productivity Reducing time to market in new product development Reducing production costs Optimizing product distribution and delivery Increasing market share Increasing customer retention Business drivers are so high level that they can apply to many different businesses. What distinguishes businesses in terms of strategies is how they prioritize these objectives and how they define and implement strategies to realize their goals. We do not need to settle for just that. we can more precisely plan our cloud services. is understanding what business objective is served by that move. moving to cloud computing because it is a more efficient vehicle for delivering computing services is a sound reason. Another company may realize that it is their intellectual property (IP) that drives their growth. For example. If we press for an even more detailed set of drivers. though.The Definitive Guide to Cloud Computing Dan Sullivan Prioritizing According to Business Drivers Business drivers are the strategic objectives of an organization that frame the need for IT services. then. Certainly. This will help us to plan for short‐term capacity demands. Still another company operating in a mature market may decide to grow by acquiring new customers by targeting perceived weaknesses in their competitor's product line. The first step in planning a move to the cloud. one company may decide to focus on increasing productivity in order to remain competitive in an increasingly global market. This is expected because businesses all have the same high‐level goals of maximizing returns for owners. as well as deploy needed applications and other software to support those objectives. and they need to invest more in computational resources to develop new IP. 84 . plan for long‐term needs.
85 . It is difficult enough to elucidate and define requirements for one application let alone gathering requirements for multiple applications serving different business needs and managed by a range of departments. we are not starting from scratch. the current application requirements. and what strategic objective is served by the application. An inventory should include all applications that might migrate to the cloud.1: Highlevel. prioritized objectives. nonprioritized business objectives are less helpful in shaping cloud computing planning than more precise. so it is important to include in the inventory key information in three areas: • • • Business requirements and related details Technical and implementation requirements Operational details and requirements Business requirements specify who within the organization is responsible for a service. policies. how critical that service is to the business. Existing Applications Infrastructure: The Current State of Affairs An inventory of existing applications and workloads is a valuable asset for planning a move to the cloud. Defining Requirements Defining requirements that will drive a cloud computing adoption can be a daunting task. These requirements are not necessarily long. detailed documents. Our job is then one of understanding the details of existing systems because these reflect. documentation. Implementation details will vary from one application to another (even among the same software used by different departments or for different business purposes). We can then build on this by assessing additional requirements going forward. at least to some degree.The Definitive Guide to Cloud Computing Dan Sullivan Figure 5. and operational procedures are probably already in place. a simple half‐page summary is probably enough. Fortunately. Applications. Our goal is not to create an encyclopedic resource on every application in the organization but to create a planning tool that highlights the services that will run in the cloud and identify the core requirements for those services.
servers. network utilization. critical dependencies Summary of key compliance and governance issues with this service Technical Operations Backup requirements Disaster recovery Compliance issues Table 5. Time to recover services. This includes details such as: • Server configuration • Workloads on servers • Dependencies and interoperability considerations • Use of shared resources. such as disk arrays. frequency of peak periods.The Definitive Guide to Cloud Computing Dan Sullivan The technical details catalog some of the implementation details about existing services. and related hardware 86 . recovery time objectives. List of servers and description of configuration. libraries. software stacks. backup servers and disaster recovery sites Description of server. such as disk arrays All the necessary details about existing services may be documented in a form like that shown in Table 5. utilities and other packages required to run the applications Commercial. backup services Operating system required. etc. level of services to be restored. Type Business Requirement Area Service Description Business Owner Service Level Agreements Business Objective Criticality Servers Shared resources used Platform Services Applications Physical distribution of servers Utilization Peak Periods Dependency on other Services Description A high‐level description of the service Person or department that funds and governs the IT service Key requirements on service delivery Describes the strategic business objective that is served by this IT service Ranking of relative importance of this service. disk array. Times and duration of peak loads.1. role of each server Shared IT resources. open source and custom applications Location of primary servers.1: Requirement categories for summarizing existing applications. network. periodicity of peak demands Other IT services that are required to deliver this service Recovery point objectives.
and perhaps the most influential in the long term. such as advanced analytics. it is that requirements will change. are more difficult to pin down. This is especially important if you are implementing a private cloud and want to ensure adequate capacity for peak demand periods. in the case of reducing duplicate data for business intelligence applications. Consider examples such as: • • • Using cloud storage to store single copies of data that are accessed by multiple applications rather than duplicating data sets Reducing the number of ad hoc reporting tools as users standardized on the "best of the breed" tools offered in the cloud's service catalog New applications. We certainly want to capture applications and workloads that fall into the "more of the same category" (for example. Public cloud customers will also find this data useful for budgeting and long‐term planning although there is no need to be concerned about the hardware capacity of your provider (at least in theory). and the amount of data we are analyzing. For hybrid cloud configurations. Assessing Workloads Workloads are as varied as business requirements. we can at least provide best estimates (sometimes guesses) for these new types of applications. Some workloads place a heavy load on CPUs while others are more I/O intensive. the implementation of the algorithms. we will be able to devise reasonable estimates on compute and storage impact of some of these new requirements. Sometimes workloads are fairly consistent over time and others have well‐defined peak demand periods. 87 . The more innovative applications. For example. the algorithms used. It is important to understand workload profiles for a few reasons. are those that change the way we do business. more departments will stand up small databases because the overhead with managing them is reduced) but the most interesting. such as statistical analysis and data mining of large customer transaction data sets enabled by on‐demand access to compute and storage resources In the best cases. The CPU demands of such applications are highly dependent on the type of analysis. These should also be captured during the requirements‐gathering stage. and consolidate resources. we can develop fairly accurate estimates. this type of detail can help you understand when internal capacity will be exceeded and public cloud resources will be required. change the way services are consumed. A move to the cloud will open new opportunities to deploy additional services.The Definitive Guide to Cloud Computing Dan Sullivan Additional Requirements for New Applications If there is one thing we can count on with IT services. Capacity Planning First. it helps to estimate the overall capacity of cloud services the business will consume. Even with these limitations. The next step in the planning process after prioritizing business drivers and defining known and estimated requirements is to analyze the potential workload for the cloud.
If it is a high‐priority job. services provided to the customers through Web applications will have generated historical data that can be used to determine demand patterns. Note This is different from a simple market model in which price is determined by supply and demand. the customer will bid less. Ideally. is subject to the same limitations as free markets. The IT department. when demand goes down. Cloud consumers can bid a price for a server or CPU time based on the value of having a particular job run. Depending on the level of control one has over the workload scheduling. the model breaks down when there is. seasonal variations such as those retailers experience just before the Christmas holiday. 88 . and networking. a cloud provider can schedule jobs in an optimal manner or use variations in pricing schedules to provide incentives for users to schedule their jobs in ways that coincide with the scheduling goals of the provider. we would have a mix of jobs that have different levels of demand on CPU. or other organization structure charged with providing private cloud services. In the case of a cost recovery model. Conventional free market economics predicts the price will drop in such situations. and load (ETL) processes running at one time. Basically the idea is that the service providers recover whatever the cost of providing a service. Cost Recovery Public cloud providers set their rates to cover costs and earn a profit. or longer. I/O. at any time. transformation. Internal service providers generally are more concerned with recovery costs than making a profit. Charges are based on a simple formula: (Total Cost of Providing Service / Number of Units Consumed) = Cost Per Unit Units of service can be CPU hours. the customer will bid a higher price. price per unit could actually go up because the number of units consumed goes down. These applications may have minor periodic variations. This approach will optimize the allocation of resources in the way a free market optimally allocates resources. This model. insufficient information or time to fully evaluate options. Cloud providers can use knowledge of workloads to optimize scheduling. One way to globally optimize scheduling is with a bid/accept model for pricing. We would not want. however. For example. will likely charge for services provided as well. and a shared cost model is a common means for charging for these services. for example. for example. for example.The Definitive Guide to Cloud Computing Dan Sullivan Scheduling Another reason to assess workloads is for scheduling purposes. if the job can wait. Some jobs have fairly predictable workloads. Mondays have heavier workloads than Fridays. to have all the I/O and CPU intensive extraction. or gigabytes of storage per month. server hours. The mix of workloads and their distribution over time are important factors when aligning requirements to the cloud model.
Legions of IT professionals are not needed to do this. we design around a number or architectural principles focused on: • • • • Designing for scalability Designing for manageability Deploying layered technical services Delivering business services Before discussing each of these in detail. Virtualization is a fundamental aspect of cloud computing and is used at numerous levels of service delivery. or hybrid cloud services. and identity management. we move away from the planning aspects and start to focus on more architecture‐oriented issues related to moving to the cloud. As the provider of cloud services. technical.The Definitive Guide to Cloud Computing Dan Sullivan Aligning Requirements to Cloud Services At the end of the planning phase. we want to have sufficient capacity. When a private or hybrid cloud model is used. We virtualize computing and storage. we should have: • • • A set of high‐level requirements for existing applications that will move to the cloud described in terms of business. 89 . An immediate benefit of virtualization is flexibility. such as database management. How we do so will depend on whether we are using public. Higher‐level services. we are both the provider (for some of the services in the hybrid case) and the consumer. To do so. and operational requirements Rough estimates for new applications enabled by the cloud Workload information that can provide the basis for capacity planning. Different software stacks can be deployed to run for some period of time and then shut down. are provided as services abstracted away from implementation details. virtualization enables greater levels of self service than have been possible in the past. As we get into these issues. content management. Architectural Principles for Cloud Services The architectural principles underlying the cloud model are designed to maximize the utility of computing infrastructure by making it available to a broad range of users for a variety of applications without unnecessarily coupling hardware and software to single uses. we have to redeploy existing hardware and/or procure additional hardware and deploy it in a cloud infrastructure along with management applications and a service catalog of machine images and related software. we have to demonstrate the provider can offer the levels of service needed at the times they are required. Hardware can run different operating systems (OSs) at different times. private. When a public cloud provider is used. scheduling. it is worth noting the importance of virtualization to cloud architectures. and cost recovery To ensure a cloud service meets the expected needs. which hides the implementation details of these low‐level services.
we can deploy single servers dedicated to single tasks. A second advantage is that hardware is fairly easily reallocated. For example. First. install machine images with other applications needed at the time. incremental increases in workloads. policies and procedures are in place to change the roles of servers fairly rapidly. A step away from the dedicated server model toward a highly virtualized environment like the cloud is a server farm in which servers are reallocated according to changing needs. 90 . at one end of the spectrum. Figure 5. the greater the flexibility in adapting computing resources to changing service needs. There are a number of advantages of this approach over the dedicated server model. If additional resources are needed to accommodate growing workloads. varies with the amount and method of virtualization. either the server needs to be upgraded or additional servers need to be dedicated to that purpose. there is no need to procure new hardware for small. This is especially costly if the additional resource requirements are only for short peak demand periods.2: The greater the virtualization and support for selfadministration. and the benefits derived from it. and redeploy the servers in their new roles. Systems administrators shut down applications and supporting software.The Definitive Guide to Cloud Computing Dan Sullivan The degree of flexibility.
This creates a certain amount of overhead cost associated with the switch. Granted. In addition. Nontechnical cloud consumers can manage their own workloads. In addition to flexibility. This can further reduce administration costs and facilitate charge backs and cost recovery. Figure 5. In a cloud environment. but it is still greater than the cost associated with the self‐ service switching costs found in cloud environments. it is still hampered by the need for IT support to reallocate resources. the process of deploying virtual machines is highly automated with the use of self‐service software. resource tracking modules in the cloud administration software can track the images used.3: Virtualization combined with selfservice administration lowers virtual machine deployment costs. and the amount of storage used by job. the time servers are up and running. 91 . it is smaller than the cost associated with switching dedicated servers. virtualization enables critical qualities such as scalability and manageability.The Definitive Guide to Cloud Computing Dan Sullivan Although the virtualized server farm is a step in the right direction.
92 . we can meet scalability demands. disks in storage arrays. Security Services in the Cloud Security in the cloud looks much like security outside a cloud environment. Some of these services and features include: • • • Security services Standardized catalog of applications A service oriented architecture (SOA) These requirements are comparable to those we find outside the cloud. Identities persist over time and should be maintained with authentication and authorization information as well as encryption keys. For cloud consumers. or at least that is not the entire story. for example. we have to concern ourselves with several security requirements: • • • • Identity management Access controls Auditing and logging Vulnerability management and threat assessment Identities are independent of workloads running in the cloud. In the case of cloud providers. cloud scalability may look like just a matter of hardware. With enough physical servers.The Definitive Guide to Cloud Computing Dan Sullivan Designing for Scalability Concerns about scalability affect both cloud providers and cloud service consumers. the designing for scalability entails addressing several requirements for meeting varying workload demands. the issues tend to be around the question of how to most effectively utilize the computational resources available in the cloud. When we deploy applications to the cloud. Cloud service providers also have to provide services and features in addition to raw hardware to enable a functional. to control limits on resource allocation in the cloud and to store keys used to encrypt data stored in the cloud. and network bandwidth. This type of information is needed. right? Not exactly. scalable cloud. Providing Scalable Computing Resources At first glance.
libraries.4: Security controls in the cloud depend on identity. and update images as needed. audit and other logs must be tamper‐proof and sufficiently detailed to meet security and compliance requirements. As in any deployment architecture. distributed database running the same database management system in different sites. or even the ubiquitous desktop OS. and upgrading. utilities. verify installation. These are all sufficiently complex to require regular vulnerability scanning. Standardized Catalog of Services Scalability often implies repeated use of a small set of constructs. and encryption keys. for example. 93 . every cloud user that deploys that image will have access to the latest version.The Definitive Guide to Cloud Computing Dan Sullivan Figure 5. a cluster of computers comprising identically configured servers. cloud providers need to support process‐ oriented auditing and logging. The images that comprise the service catalog will support a wide range of OSs. access control lists. track patch levels. These examples show that benefits of standardization can often outweigh the disadvantages of not having customized solutions to a particular problem. patching. One of the advantages of cloud architectures is that once an image is scanned or patched. Cloud providers will also need to have procedures in place to perform vulnerability scans on images. and applications. There is no need to push patches to servers or desktops. In addition to user‐centric security information. Take. and then manually correct failed patches.
Scalability in the cloud requires providers to plan for and support security services. 94 . so the retailer will deploy multiple Web servers each hosting the same content. such as a service that is provided only on a single server. however. SOAs decouple services through agreed upon interfaces and message passing. Scaling with Round Robin Load Balancing Consider an online retailer that experiences peak demands during the holiday shopping period. Scalability requires design and implementation considerations beyond those of just hardware and infrastructure. Cloud users are still free to bring or develop their own custom applications. As other parts of the application scale up to meet demands. The data we collect in the planning stages about application requirements can form the basis for building the service catalog. it is even more important. standardization at the platform and application level comes with a standardized catalog of services. we have the possibility of running a large number of services under varying workload conditions which are subject to different constraints. when we are working with highly‐scalable architectures such as the cloud. so scaling their Web site with cloud‐based applications makes sense. Cloud users can instantiate virtual machines running images from the catalog. In the cloud. that service would be bound by the constraints of the single server. In this way. a wide range of inputs and outputs. Two common ways of avoiding this type of bottleneck are to distribute workloads in either a round robin manner or by partitioning workloads. scalable. but the service catalog provides a supported foundation for all cloud users. a standardized catalog of services. no single server becomes a bottleneck and additional Web servers can be deployed from the cloud if needed. The holiday season lasts several weeks. we as cloud consumers need to use application architectures that take advantage of the cloud's underlying scalability. This model scales to different types of services. This requires that our applications avoid processing bottlenecks. and can scale to a large number of services. There will be many users all accessing the Web site and most of the demands on the server will be to deliver Web pages. A load balancer receives all HTTP requests from shoppers and distributes them evenly across all the Web servers.The Definitive Guide to Cloud Computing Dan Sullivan In the cloud. there should be as few dependencies as possible between applications. and an SOA. In environments such as this. by definition. Cloud providers have to weigh the benefits of adding specialized images to the catalog against the additional overhead of managing more images. Furthermore. Using Cloud Services in Scalable Ways A cloud architecture is. SOA Services in any architecture have to be sufficiently accessible to be of use. to realize the full benefit of the cloud. this approach provides high availability as well because the failure of any one Web server will be compensated for immediately by other servers in the cluster.
For example. This helps to ensure scalability because no one server supporting a partition would become overloaded faster than the others. if a geographic partitioning scheme is used and one area grows faster than the others. Also. it can help long‐term maintenance if the partitioning scheme allows for changes to the partition criteria without significant overhead. Partitioning by Data Characteristics Another way to scale applications is to divide workloads by some characteristic of the data: • • • • Geographic location of customer Distribution center fulfilling an order Product category Customer name Ideally. the next connection or transaction is assigned to the first server in the list.5: Round robin load balancing assigns each new connection or transaction to the next server in an ordered list of servers. one could subdivide the fast‐growing geographic area into two subdivisions. the criteria for dividing a workload will lead to roughly equal size partitions of the data.The Definitive Guide to Cloud Computing Dan Sullivan Figure 5. 95 . when the last server is reached.
Databases use a combination of in‐memory caches and persistent disk storage. Figure 5. multiple instances of a database can run on multiple servers. Nonetheless.The Definitive Guide to Cloud Computing Dan Sullivan Partitioning data and storing it in different databases is sometimes used when a single database server cannot keep pace with workloads. presumably. Each server will maintain a cache of partitioned data and. Geographic distribution is especially helpful in localizing network traffic and improving the responsiveness of applications that run on the same local network as the database server. In the cloud. The total amount of memory available for caching is the sum of cache memory across all database servers. In the cloud. use cloud storage for persistence. Queries that can be answered using cached data are significantly faster than those that require disk operations. this type of partitioning is still useful for performance. This can result in a much higher ratio of queries being answered from the cache rather than from disk. 96 . this is less of a concern at least for the cloud service consumer.6: Partitioning data across multiple database servers can improve the scalability of dataintensive applications.
the user shuts down the server. In the simplest case. 97 . a workflow may require six virtual servers running a Java application server and a load balancer for distributing transactions across the six other servers.The Definitive Guide to Cloud Computing Dan Sullivan Designing for scalability is concern for both cloud providers and cloud consumers. the more efficiently a cloud can deliver services to its users. Even in a simple case. Three key points in this area are: • • • Provisioning Monitoring Usage and accounting The more these services can be automated. and an SOA are also essential for ensuring scalability. This is a fairly straightforward task but still requires management software to allow non‐IT personnel to manage the process. but those are not the only scalability issues they face. there are issues: • • • • • • Selecting a machine image to run on the virtual machine Determining the time to start the virtual instance Deploying additional applications needed to process the particular workload Starting services on the virtual machine Executing a workflow Shutting down the virtual server Provisioning operations can be more complex if they involve multiple instances running different applications. and after running a process. The servers may be shut down at different times as the workload varies or other application servers may be added to the set of servers to meet peak demand. Security. For example. a standardized catalog of applications. Designing for Manageability Manageability is another architectural principle that strongly influences how we implement and consume cloud services. Cloud consumers also have a role in ensuring scalability by designing their applications appropriately using techniques such as round robin load balancing and data partitioning. Managing Cloud Provisioning Provisioning in the cloud is the process of instantiating one or more virtual servers running a particular machine image. This is an important principle for both cloud providers and consumers. Providers need to address obvious hardware and networking infrastructure issues with scalability. Easy‐to‐ use software is essential to low‐cost provisioning. a user needs to start a single server.
there are easily controlled marginal costs associated with running jobs in the cloud. and costs for those resources This type of monitoring is primarily for managing running jobs. This includes tracking: • • • • CPU and memory utilization to determine whether additional resources are required or some should be shut down Disk I/O to ensure sufficient throughput on I/O operations to meet requirements and service level agreements (SLAs) Application logs to look for adverse events or warnings of potential problems Jobs and workflows running in the cloud. these reports show aggregate information about: • • • • • Who is using cloud services Number of virtual servers run per job and the duration of jobs Machine images instantiated in the cloud The amount of storage in use The amount and type of I/O operations Cloud users may find these reports especially useful for optimizing how they schedule jobs. 98 . There may be cost advantages to running jobs on larger servers but running fewer instances when the pricing scheme provides such an advantage. and usage and accounting reports from the start. resources used. Usage and Accounting Reports Usage and accounting reports are especially important for verify billing and analyzing trends in cloud usage. There may be advantages to aggregating jobs and running them less frequently. Designing for manageability means planning for end user provisioning. This can be the case when cloud providers charge in minimum units of one hour and jobs are consistently finishing in well under one hour. Unlike running a dedicated server. It is also important to have management reports that summarize jobs. we will need to monitor them.The Definitive Guide to Cloud Computing Dan Sullivan Monitoring Jobs in the Cloud Once servers are provisioned and jobs are running. For providers. including running time. and costs over longer periods of time. resources allocated. process monitoring. Cloud service consumers should make use of these reports to run their jobs in the most efficient manner possible.
each providing service to the layer above with the topmost layer providing end use business applications. cloud services are layered as: • • • Infrastructure services Software platforms Applications and information services Infrastructure services are the lowest‐level service and include virtual machines. portals. like virtual memory. 99 . and so on. content management systems. At the most course description. we run middleware software such as relational database management systems. OSs have long used layering to isolate the need to deal with hardware‐specific issues or manage low‐level operations. Java application servers.The Definitive Guide to Cloud Computing Dan Sullivan Deploying Layered Technical Services Layering services is a long‐standing approach to dealing with software complexity. We'll veer from the normal case here to address one other essential part of delivering and consuming cloud services: the need for managing service delivery. virtualized storage. Layering services is a sound approach in cloud environments as well. Delivering Business Services Usually we would stop discussing architectural principles once we reach the top of the application stack where business services are delivered. and customer‐facing Web applications. business intelligence reporting systems. Figure 5. On top of this layer. This middle tier provides the building blocks for business‐specific applications such as customer relationship management (CRM) systems. and network services.7: Cloud services are delivered in layers.
as currently implemented.The Definitive Guide to Cloud Computing Dan Sullivan The service catalog discussed earlier is part of this process. such as the following. not essential for core day‐to‐day operations but a long‐term priority). In particular. In the next section. this is commonly known as churn. the company reviews the business. technical. Second. The service catalog has its own long‐term maintenance issues. it will allow customers to access their entire account history rather than just the past 4 months. The business area requirements focus on this imitative as mid‐level criticality (that is. Business Services in the Cloud: Use Case Scenarios We will consider two use cases: a new customer service initiative and a business intelligence application. just as software distributed throughout the organization. New Customer Initiative Use Case The first use case scenario is motivated by the business driver to improve customer retention. the contents of the service catalog are driven by existing and anticipated business requirements. the company has decided on a two‐pronged approach. it will provide more targeted offers based on a customer's account history. we will turn our attention to two use cases to provide examples of applying the planning process and architectural principles to typical business requirements. Basic policies. We will also examine some of the workload considerations that factor into managing cloud‐based services. Servers are generally concentrated in the data center and there is less need for maintaining desktop clients. 100 . As part of the planning process. A company has been experiencing moderate but increasing turnover in the customer base. As noted. should be in place: • • • • • • Pricing and cost recovery Patch management Security policies Acceptable usage Auditing Data retention Policies define how cloud services will be governed and managed and provide the final piece of the planning processes for deploying business services in the cloud. In an effort to reduce churn. the company has determined that it can gain a competitive advantage over others in the market by improving customer experience. One of the advantages of the cloud is that service management is less complex. Policies are needed to govern cloud operations and services to ensure their long‐term stability.1 for a list of requirement categories). and operational requirements for these services (see Table 5. First.
They can be deployed around dedicated department‐level servers and storage. the number of customers querying their account histories each day. the server runs well below capacity. Another potential area of significant inefficiency is in storage. Compliance requirements are minimal. Traditional data warehouses and similar business intelligence architectures inefficiently allocate resources. The need for additional compute resources can be met by the cloud as well. and materialized views. It can be difficult to estimate storage requirements. Business Intelligence Use Case A company has decided to consolidate its business intelligence reporting services to improve the efficiency of business intelligence operations and lower overall costs. Analyzing customer account history to generate custom offers is a compute‐intensive process but will not require significant additional storage. and the processing load required to update account histories on a daily basis. disaster recovery. This is a customer‐facing Web application. The incremental growth in storage required to accommodate new customer activity is also readily met by the cloud. The best combination of optimization techniques may not be discovered until the business intelligence system has been in use for some time. 101 . may be used to improve performance. The peak CPU demands generated by this process will last for 1 to 2 days. such as excessive indexing. because this is a customer‐facing application. especially when various performance techniques. The service catalog already supports the middleware required. Unless there is high demand for ad hoc queries outside of data loads and report generation operations. This tends to lead to low CPU utilization between data loads and report generation. but company policies protecting private customer information must be followed. In a traditional deployment. that storage hardware would have been purchased already. customer identity management services. Operational requirements include backup recovery and. That inconvenient fact often leads to purchasing more storage than is needed for fear of not having adequate storage. including the database. The requirements are well met by cloud architecture. and statistical analysis software. One of the defining characteristics of business intelligence and advanced analytic operations is that they entail large amounts of data and they are computing intensive. Each of these platform services is available in different images. Estimates are compiled on the amount of data that will be stored. portal. denormalization. and access to a portal to provide presentation‐level services. so each will be running on one or more virtual machines. Accessing entire account histories for all active customers requires the ability to rapidly scale both computing and storage resources. so the portal servers will be configured in a load‐ balanced cluster and the data will be partitioned to evenly distribute the customer database over multiple database servers.The Definitive Guide to Cloud Computing Dan Sullivan The technical requirements include platform services such as relational database management services. This type of analysis will be done periodically but not more frequently than once a month.
the marketing department and the quality control group may both want to use sales data but in different ways. monitoring. For example. loading schedules can be optimize to increase utilization by performing extraction and copy operations during times when there is a low demand on cloud resources.The Definitive Guide to Cloud Computing Dan Sullivan Business intelligence as a cloud service can be implemented more efficiently. An additional benefit is that a single copy of data can be shared among different departments. Similarly. In cases where each department maintains its own data mart. these applications can meet the requirements of the business drivers that motivate their development. and they can be managed using the self‐service provisioning. such as development and test environments or collaboration services. then scale back to a smaller number of servers. the peak demand period is over but an estimated 25% of peak computing resources will be needed during the rest of the data for ad hoc reporting. they can be deployed using the infrastructure. platform. Both of these use cases demonstrate common characteristics of business services that fit well with the cloud model: • • • • Minimal or moderate security requirements Minimal dependencies between services Moderate audit requirements Minimal customization As a result. 102 . reports will be generated. Once the ETL process is complete. workloads can be mixed so that some I/O intensive jobs are run at the same time as other CPU intensive jobs that can run at the same time as jobs with more constant and predictable workloads. The same data marts can run in the cloud but share a single copy of the source data. The cloud allows this initiative to start servers as needed for the ETL and reporting operations. and application services provided by the cloud. Technical requirements include large volumes of storage and a large number of servers to perform ETL operations to populate and update the data warehouse on a daily basis. Once the reports are complete. Mixing Workloads Jobs that do not need to run on strict time schedules can be arranged to optimize utilization. the sales data would be duplicated. For example. Let's assume the business drivers behind this project include improving sales by providing detailed and timely reports to sales managers while reducing the total cost of business intelligence services in the company. and usage accounting services provided by the cloud management software.
start with the business drivers and ensure that services deployed in a cloud support those drivers. scheduling. 103 . monitoring. Manageability is also a factor in realizing scalable services. Also understand workloads and related issues. be sure to analyze requirements in terms of business. and usage reporting. especially related to provisioning. To do so. Scalability is essential. technical. software. we will delve deeper into technical and architectural issues with a look at identifying further details of cloud architectures and their impact on your business. Cloud service providers ensure scalability by providing sufficient hardware. such as capacity planning.The Definitive Guide to Cloud Computing Dan Sullivan Summary When formulating a strategy for moving a business to adopt cloud services. On the planning front. and operational needs. and networking services but also by supporting security services and a standardized catalog of applications in an SOA. and cost recovery. In the next chapter. Key architecture and design consideration also have to be taken into account by cloud service providers and cloud service consumers. we should bear in mind both business planning and architectural considerations.
a pay‐as‐you‐go funding mechanism. and high levels of self‐service) allow cloud providers to deliver a wide range of services using a number of implementation models. The model lends itself to a range of implementations with no single architecture constituting a "true cloud" architecture. we will examine several aspects of selecting a cloud architecture: • • • • • • • Levels of cloud architecture Issues in providing compute services Issues in providing storage services Considerations for network services Cloud operations management Service layers and adapting IT operations to infrastructures Topics in service management We will start with a brief review of architectural elements common to all cloud architectures. This is hardly surprising.The Definitive Guide to Cloud Computing Dan Sullivan Chapter 6: Identifying the Right Cloud Architecture for Your Business Cloud computing is a general model for delivering computing and storage services. The defining characteristics of cloud computing (the ability to allocate and release compute and storage resources on demand. 104 . This range of variability means businesses can choose the right cloud architecture for their environments. In this chapter.
for example. files systems. An application programming interface (API) for storage allocation may make calls to additional services that are not available outside of the storage system. There is no need to delve into details about directory structures. or disk configurations. it makes a call to a storage service requesting a particular amount of space. layers in a cloud control the potential complexity of cloud design by following a few basic principles: • Services are provided as logical abstractions that hide implementation details. When a program needs to allocate additional storage. Services are provided at a functional level appropriate to the users or services that consume the services. when allocating new storage. the broader and more business oriented the services.The Definitive Guide to Cloud Computing Dan Sullivan Levels of Cloud Architecture Cloud architectures can be thought of in terms of layers of services in which each layer depends on services provided by the next lower layer. upper level services might initiate business process workflows. For example. 105 .1: Cloud architectures can vary in detail and levels of services provided but most include some combination of infrastructure. • • Figure 6. platforms. Services are isolated to appropriate layers in the architecture. Although lower‐level services might operate on storage blocks. and services management. an API procedure might call an isolated procedure to add the allocated disk blocks to a list of blocks that are replicated to storage devices for backup and performance reasons. The higher up the stack of services we go. As with other layered models of abstraction in software engineering.
Virtualization of Resources One of the hallmark characteristics of a cloud is the virtualization of resources. For example. such as the Transaction Processing Performance Coucil's (http://www. The ability to hide implementation details without adversely affecting services is essential to providing cloud computing. (We will focus primarily on server virtualization here and address storage virtualization later in the section entitled "Providing Storage Services. One of the first advantages of this approach is that we can work with a standardized set of features. databases. 106 . One could also define virtual servers in terms of performance relative to standard benchmarks.tpc. we can think of three coarse‐grained levels of services in a cloud architecture: • • • Virtualization of resources Services layer Server management processes Each of these levels can be further subdivided. Virtualization can be thought of as a way of abstracting computing and storage services away from implementation details and toward a more logical and less physical view of resources. decision support benchmark (TCP‐H).The Definitive Guide to Cloud Computing Dan Sullivan Broadly speaking.") Logical Units of Computing Resources Server virtualization allows us to manage compute resources in finer‐grained units than just a physical server allows. we do not think of the implementation details about these services. a standard virtual server might be equivalent to a physical server with one Intel Xeon 5600 series or AMD Opteron 6000 series processor and 8GB. such as the number of CPU cores and amount of RAM. By decoupling how we allocate computing resources from the underlying hardware that provides those resources.org/tpcc/default. email servers. and other business applications. Many of us use virtual servers routinely although we might not know it. we gain flexibility in managing how we consume compute services and manage them. Virtualization is especially important for efficiently using computing and storage infrastructure. We connect to servers across the Internet that run Web sites.asp) online transaction processing (OLTP) benchmarks (TPC‐C and TPC‐E) and the ad hoc. Most of the time. Is the email server running on a single physical server? A cluster of load‐balanced servers? Or perhaps the application is hosted on a virtual server that shares a physical server with several other virtual machines running an entirely different set of applications. How the logic units are defined is less important than the fact that we have a standard for allocating computing resources that is not tied to a particular physical implementation. at least from our perspective. These details are often unimportant.
For example.The Definitive Guide to Cloud Computing Dan Sullivan Figure 6. The first time a cloud consumer runs a job. and provides for a straightforward pricing model that consumers can use for planning and budgeting. It directly enables the most efficient allocation of resources. Standardized Service Pricing Along with logical units of computing resources and hardware independence.2: Server virtualization allows cloud service consumers to use standardized units of computing services without concern for the physical implementation details. the next time the same job runs on the other type of server. 4. virtualization allows for standardized service pricing. the job might run on one of the more energy efficient servers. it has a direct impact on how cloud service consumers plan and manage their use of the cloud. Virtualization of services is an essential element of a cloud architecture. Cloud providers can deliver those logical units using the most economical way possible. The less energy efficient servers are only used when the more efficient servers are running at peak capacity. a cloud might have several types of physical servers running in the cloud. Hardware Independence Another advantage of virtualization for cloud service providers is hardware independence. reduces the need for cloud service consumers to understand the nuanced differences in physical servers. 107 . or 8 core server. Cloud consumers can allocate the level of computing resources they need without having to worry about whether a particular physical server is a 2. Although this is not a technical issue.
The Definitive Guide to Cloud Computing Dan Sullivan Services Layer The services layer is another common characteristic of cloud architectures. OSs of course are included in the virtual machine images. At the highest levels. 108 . Services such as those shown in Figure 6. It is certainly possible to provide a cloud that offers only infrastructure services (that is. Persistent storage services. some of which build on others within the same layer. business applications such as CRMs and ERPs may be provided as Web applications that run in the cloud. the services layer can provide additional benefits.3: The services layer consists of a wide range of service types. Figure 6. Higher‐level services.3 might be delivered in different ways to customers. such as block storage and relational database services. but other services might be independent of virtual machine instances. and workflow engines. At this level. portals. might be embedded within virtual machine instances along with other software stack components. we work with not just virtualized hardware but also operating system (OS) and application services. At this level. but for business users of cloud services. service consumers are completely divorced from implementation details and are solely concerned with business‐related functionality. might be available as services available to all virtual machine instances running in the cloud. such as application servers. the virtualized equivalent of bare metal machines).
Usage accounting and management reporting are necessary for billing or charge‐backs on the part of cloud service providers and for cloud service consumers who must plan and manage their budgets for IT services. software stacks. These include: • • • • • Virtual machine image management Image deployment Job scheduling Usage accounting Management reporting The first two of these services supports a catalog of images preconfigured to particular applications. one time jobs that can be submitted to run in the cloud as services are available.4: Management reporting serves the needs of both cloud service providers and consumers. Job scheduling services are especially useful when services pricing varies by point in time demand or time of day. or OSs that can be deployed by cloud service consumers. Job scheduling applications help with routine processes that run repeatedly on a schedule as well as large. 109 . Figure 6.The Definitive Guide to Cloud Computing Dan Sullivan Service Management Processes A third major aspect of cloud architectures are the service management processes that support the delivery of services.
This can significantly reduce compliance issues with cloud computing. The remaining sections of this chapter will delve into those factors. Businesses that choose to provide private clouds or hybrid private/public clouds must be in a position to provide the physical infrastructure and basic management services needed in a cloud. Hardware Selection Hardware selection for clouds depends upon two competing interests: controlling costs by redeploying existing hardware versus acquiring a standardized server platform that is configured specifically for cloud computing. 110 . cloud architectures can be described in terms of infrastructure. Private and confidential data is not moved outside the company. as cloud applications while using a public or other third‐party physical infrastructure. services. Using existing hardware can lower initial capital expenditures but might lead to higher costs over the long term. Older machines that require more maintenance. An advantage of new hardware is that the cloud can be configured with standard servers optimized for cloud computing: large numbers of CPU cores.The Definitive Guide to Cloud Computing Dan Sullivan To summarize. Standardization also helps reduce maintenance costs. including potential competitors. Businesses maintain total control over computing resources with a private cloud. With the advantages come additional functional responsibilities. high speed I/O for connections to disk arrays. Multiple factors will determine the best choice of architecture for a particular set of business requirements.) Those that will deliver computing services directly though a private cloud should consider: • • • • Hardware selection Implementing virtualization Failover and redundancy Management reporting A business' ability to address each of these issues can strongly influence their success in delivering computing services in a cloud. data destruction policies and procedures are defined by the business. need parts that are difficult to procure. (Businesses can provide higher‐level services. or consume more electricity can have a larger total cost of ownership than new servers. Providing Compute Services There are compelling reasons to adopt a cloud architecture that include an internal or private cloud. Variations in these layers allow for different types of cloud architectures. One option is to use existing hardware initially and replace it over time as the cost of new servers becomes competitive with the cost of continuing to operate the older devices. and systems are not shared with outsiders. significant amounts of memory. and so on. and services management. such as enterprise applications.
virtualization in the cloud requires more management services than typical in IT environments. Virtual machine images are deployed to other physical servers until the failure is corrected. Conventionally. however. Clouds are inherently redundant. for example. This reduces the challenge of providing failover services. Failover and Redundancy An advantage of cloud architectures is that we move away from tightly coupling applications and services to particular physical or virtual servers. Additional controls are available in some environments that support virtual machine migration from one physical server to another. If a physical server fails for any reason. A knowledgeable user should be able.The Definitive Guide to Cloud Computing Dan Sullivan Implementing Virtualization Many organizations use virtualized servers outside of clouds. This is especially useful in situations in which a single server is running at or near capacity and one or more of the virtual machines needs to be moved to a less utilized physical server. Even this. Applications are run on virtual servers that meet a set of configuration requirements defined by the cloud service user. not the application level. Figure 6. does not meet the level of virtualization management needed in a cloud. Clouds should support end user management of computing resources. Applications that are well suited for the cloud do not need specialized hardware or a particular server. managed virtual servers are installed by systems administrators and run for extended periods carrying out a fixed set of functions. to select a virtual machine image from the catalog and instantiate a specified number of virtual servers. it can be removed from the pool of available resources. though. This type of failover and redundancy is at the server level. 111 .5: Providing computing services in a cloud requires significant support software. such as services for selecting and instantiating virtual machine instances.
storage. For example. so there is not much incentive to monitor server use as long as it does not adversely affect performance. if the application provided stateless Web services. either virtual or physical. Management Reporting Different types of management reports are required when providing computing services in a cloud. a server configuration that supports failover and redundancy. The analytic servers would run at higher utilization and for shorter periods of time reducing the overall cost of the process. With a pay‐ as‐you‐go pricing model. Cloud service consumers can use and should expect detailed usage reporting. 112 . The business process owner is paying for sole use of servers. if analytic servers are running at 40% utilization because they are dependent on data preprocessing operations that are not processing data fast enough. virtualization management and deployment systems. and network services Detailed utilization information will help business process owners optimize their applications. as well as robust management reporting. additional servers could be instantiated for preprocessing. the business owner of a process is responsible for identifying the servers needed to support a business process and covering the cost of the servers. In this model. there is fairly little to report outside of utilization rates. Cloud service consumers can use reports detailing: • • • • • Number of virtual servers allocated to a job and the time the servers ran Peak and average utilization rates of servers Amount of data stored persistently Amount of data transferred across the network Charges for compute. recovery would depend on the application. Presumably the cost of running the additional preprocessing servers would be offset by reducing the length of time the servers have to run. In a traditional "one server‐one application" approach. the application could also recover fairly robustly on another virtual machine. In cases where the application writes state information to persistent storage and checks for prior execution information each time the application starts. Providing computing services in a private or hybrid cloud requires a combination of hardware. it could be restarted on another virtual machine instance on another physical server and start responding to service requests again. For example.The Definitive Guide to Cloud Computing Dan Sullivan If a physical server were to fail while an application were running on it. there is an incentive to allocate the fewest number of virtual servers and run them for the shortest time possible while still meeting business requirements.
The advantages of virtualized storage are similar to those of virtualized servers: • More efficient use of storage—rather than dedicating large units of storage to a single use for extended periods of time. Multiple virtual machines can access the same storage blocks and the data continues to exist regardless of how virtual machines are started and stopped. Local vs. details like the logical unit number (LUN) mappings to storage volumes and storage devices are managed by storage virtualization software. storage is allocated in smaller increments and for only as long as it is needed Lower capital expenditures for individual projects and business units that do not have to acquire storage hardware Lower operating costs associated with the pay‐as‐you‐go model typical in cloud computing storage More efficient delivery of backup and recovery services • • • This last benefit is especially important. the cloud services consumer simply makes a call to a programming interface specifying the amount of storage required. The persistent cloud storage described here is provided by devices that are independent of virtual machines. like server virtualization. Consumers of these services can allocate resources without concern for implementation details. it will have to provide storage services as well. 113 .The Definitive Guide to Cloud Computing Dan Sullivan Providing Storage Services If a business moves forward with providing private cloud computing services. abstracts the services provided by hardware. The data in this storage is lost when the virtual machine is shut down. When persistent storage is needed. For example. This would require additional support services: • • • Storage virtualization Backup or other redundant storage Disaster recovery Storage Virtualization Storage virtualization. Cloud Storage Virtual machine instances can provide local storage for temporary storage during the life of the virtual machine instance.
the data is immediately available from another device. One of the advantages of virtualized storage is the ability to provide large amounts of storage through a single logical device—the storage cloud. Users can also benefit from improved performance with multiple copies.The Definitive Guide to Cloud Computing Dan Sullivan Figure 6. of course. This setup creates an opportunity to replicate data across multiple storage arrays to improve reliability and performance. we have multiple disk arrays possibly located in different facilities. different queries can be served by different copies of the database. Users contending for access to a single copy might experience bottlenecks and associated drops in performance. In the cloud. A background replication process can add new or changed blocks to a queue of blocks that will be copied to devices. The particular device that returns the data is irrelevant to the user. 114 . Replication can be done asynchronously so that I/O operations return as soon as data is written to the primary storage device. If a storage device should fail. Data warehousing and business intelligence applications often query large amounts of data. Behind the scenes.6: Cloud storage systems can use data redundancy to improve data management performance and reliability of data services. relieving contention for the same resource. there is no need to restore from backup tape. Reliability is preserved because multiple copies of data are available.
Backups and Cloud Storage Data replication as just described is a valuable asset in cases of disaster recovery. This type of replication does not eliminate the need for backup. users could be re‐routed to another data center that maintains replicated copies of the lost data. so any errors generated in the source system will be replicated to other storage devices as well. examples include previous day at midnight. a previous time in the same day. there would be no way to restore the database back to a point in time before the error was introduced. RTOs define the maximum period of time between request of a restore operation and the time the restore operation completes. Without a separate backup copy of data.The Definitive Guide to Cloud Computing Dan Sullivan This type of replication also supports disaster recovery. however. but it cannot meet all recovery requirements. In the event of a catastrophic failure in one data center. 115 . An RPO defines points of time in history that can be restored. Figure 6. which improves reliability and performance. The ideal replication solution maintains multiple copies of data in near real time. Backup services are generally specified in terms of recovery point objectives (RPOs) and recovery time objectives (RTOs). or in the case of highly volatile databases. previous end of week.7: Storage virtualization supports data replication across data centers.
Private cloud providers might also depend on public Internet providers. Source data is backed up from the cloud and written to cloud storage. If backup software supports direct reads and writes to cloud storage. or other billable unit Cost of storage by type. The key issues we must consider when evaluating different cloud architecture options are: • • • Capacity Redundancy Management reporting Capacity Network capacity limits the amount of data that can move between data centers and between cloud service consumers and the cloud. The process could be as simple as copying and compressing data files or block storage from one storage area to another. Businesses that deploy shared disk arrays will probably have a storage reporting system in place that provides much of the needed functionality: • • • Reporting on storage used by project. Together with networks services. but cost is a limiting factor. Dedicated network connections can be employed between sites. especially for access from remote offices or smaller corporate facilities. such as primary storage versus archival storage Trending reports on growth in storage use Infrastructure managers should have additional detailed reports on such things as replication performance.The Definitive Guide to Cloud Computing Dan Sullivan Traditional backups are easily accommodated in the cloud. Network Services for Cloud Computing Networking can be the most resource constrained part of cloud infrastructure. Management Reporting for Storage Virtualization A reporting framework. they constitute the core infrastructure for cloud services. Public cloud providers are necessarily dependent on public Internet providers for connectivity between their data centers and their customers. Storage virtualization and server virtualization share many of the same benefits and management requirements. department. This directly affects a number of services within the cloud. is required for storage virtualization as well. 116 . similar to one needed for server virtualization. backup processes can take advantage of incremental and differential backups reducing the total amount of space needed to store backup files.
the problem spans industries such as financial services. it includes a scalable database (HBase). Loading Data into the Cloud Cloud computing is an ideal approach to analyzing large amounts of data. for instance. that given the mean time between failures (MTBF) on disk drives. 117 . government. retail. In some use cases.The Definitive Guide to Cloud Computing Dan Sullivan Intra‐Cloud Replication From an infrastructure management perspective. data may be generated outside the cloud by sensors and other instrumentation. In other cases. such as national intelligence and astrophysics. pharmaceuticals. and a coordination service for distributed applications (ZooKeeper). As noted earlier. high‐performance cloud. the phrase "Big Data" has become a moniker for use cases where traditional data management methods break down. this is only a problem during the transition to cloud computing when initial data is loaded. Network services require similar redundancy to avoid a single point of failure. This means that all data loaded into the cloud plus data generated or updated by cloud‐ based operations will need to be copied over the network four times. today. It is not always practical to move large amounts of data over networks to load it into the cloud. they are removed from the pool of available resources. a data warehouse infrastructure (Hive).apache. data is retrieved from another device with a redundant copy of the data. we would need to design network capacity to meet large‐scale data transfers over the long term. data is generated in the cloud using cloud‐based servers. When storage devices fail. When servers fail. The need to deal with multi‐terabyte and even petabytes of data used to be a problem limited to specialized niches. and life sciences. Redundancy in the Network Both computing and storage services in the cloud use redundancy to mitigate the risk of failures. after that. in such cases. In such cases. Hadoop and Related Tools Hadoop is an open source implementation of the map reduce model made famous by Google. a high‐level data flow language (Pig). In fact. Cloud administrators might determine. Network capacity can be a limiting factor in cloud architectures if a large amount of data (relative to network capacity) has to be moved into the cloud. ship hard drives to data centers). network capacity and speed directly affect replication. Heavy demands for loading data into the cloud not only create demand to get data into the cloud but also lead to additional network I/O due to replication. replication is an essential element of creating and maintaining a reliable. In addition to supporting massively parallel processing over clusters of computers. it is best to bypass the network and employ a cloud version of "sneaker net" (that is. cloud‐stored data should be replicated four times to reduce the probability of data loss to whatever threshold they have defined. Businesses with large data sets can leverage large numbers of servers to process and analyze "Big Data" in parallel using platforms such as Apache Hadoop (http://hadoop.org/).
Aggregate reporting over extended periods of time are also needed to determine baseline usage rates. Management reports can be especially useful if they provide a detailed breakdown of network use by time period and by job.The Definitive Guide to Cloud Computing Dan Sullivan Figure 6. For example." the cost of network I/O can exceed the cost of computing and storage resources.8: Redundant network connections are necessary between data centers as well as to the Internet. Management Reporting Cloud service users will be interested in network use reporting as a means to control costs and to monitor trends in network usage. We should not underestimate the cost of network services. when dealing with "Big Data. 118 . cyclical patterns of variation in network utilization. and long‐term growth trends.
119 . In addition to the requirements mentioned. but once a virtual machine is shut down. Management reporting is required in all three areas. scanned for vulnerabilities. of course. it can provide data for estimating future demands on various cloud resources. These are tasks associated more with overall cloud management than with individual uses of cloud services. The catalog constitutes the baseline set of services provided in the cloud. duration of jobs. Machine images can include a fairly wide range of software in addition to the base OS: • • • • Application servers Software libraries Analytic software Business‐specific applications The base OS as well as the optional software will need to be maintained over time. If metadata about previously run jobs—such as number of servers used. image management and workload management. Each of these components are provided in redundant manners supporting reliability and increased performance. there are further demands for operations support. Job scheduling software is useful for queuing large jobs or for repeated jobs in the cloud. Users can install additional services. those changes are lost. computing services. and storage services are the foundation of cloud computing. amount of network I/O. Each image in the catalog will have to be routinely patched. and rebuilt as new versions of core components become available. and so on—is collected. the cloud catalog constitutes the set of applications and platforms that can run in the cloud. in particular. Cloud Operations Maintaining an efficient cloud operation requires management support mechanisms in addition to those previously described. Image Management A cloud can only instantiate the virtual machine images available in the cloud's catalog. The next time that system is required. The information managed in the job scheduler is useful for tracking future use of cloud services. For many situations. Workload Management Workload management functions can vary from basic job scheduling to job optimization. the additional software must be installed again.The Definitive Guide to Cloud Computing Dan Sullivan Network services.
The Definitive Guide to Cloud Computing Dan Sullivan Clouds. If network resources are in high demand at night. the hourly price for servers is reduced. the price is higher than in the day. Software for cloud operations such as image management and workload management are necessary to ensure clouds operate in an efficient manner. storage. like any other IT resource. can be optimized. Figure 6.9: Demand for cloud resources can be smoothed by varying the price of services to shift demand away from peak periods to lowdemand periods. For example. This type of skewed demand schedule may be smoothed by adjusting price of services. This may lead to peak demands that are significantly higher than low demand periods. such as virtual servers. Up to this point in the discussion. users may run most data loading jobs at night. If demand for computing servers is low in the early hours of the business day. 120 . All things being equal. Information technology services also provide high‐level functions. leading to periods where demand exceeds capacity while network capacity is underutilized during the day. and network I/O. users might prefer to run large jobs overnight and shorter jobs during the workday. we have focused on lower‐level services. and management of those low‐level services.
121 . Alternatively. and high‐speed network interconnections. each server can receive a subset of data from a distribution node. These applications are ideal candidates for deploying to a cloud. business services. multiple distribution nodes could run simultaneously and use persistent cloud storage to maintain the queue of data sets that could be read by any of the distribution nodes. An application that depends on a large pool of servers to analyze data should address questions such as: • • • • What happens if a single server fails? Will the job have to be restarted from the beginning? Is there a way to detect what data was being analyzed when the server failed? Is there a way to roll back to a prior state without starting from the beginning? There are many design choices for addressing these types of questions. if a server fails while analyzing data. there are many others. In this way.The Definitive Guide to Cloud Computing Dan Sullivan Services Layer: Adapting IT Operations to Cloud Infrastructure The cloud is an ideal platform to run many. shared storage devices. This is just one example of a resilient application design for distributed computing. the data will simply be sent to another server for processing. For example. To avoid a single point of failure. taking advantage of clusters of servers. When the distribution node receives a message that a data set has been analyzed. it is removed from the queue. although certainly not all. Many business applications are already running on distributed platforms. Designing for Recoverability Recoverability is an issue at the application level as well as at the infrastructure level. but cloud architectures influence how we address them. Applications written to take advantage of mainframe capabilities and tuned to run on mainframe OSs are probably best run on that platform. this solution would also require a failover mechanism to start another distribution node should the primary one fail. The distribution node maintains a queue of data sets to distribute to analysis servers. but there are still additional factors that should be considered when moving systems to the cloud: • • • • Designing for recoverability Managing workload Performing maintenance and upgrades Maintaining security These are all considerations in service delivery.
In particular. and optimization of resources. and network services from both the service provider and the service consumers' perspective. workload management. This overlap and shared need for support service continues as we consider the service management layer. we have considered core computing. Service Management Layer A final piece of the software and infrastructure architecture that makes up a cloud is the service management layer. Throughout this chapter. In addition to access controls. appropriate application‐level controls will have to be in place to prevent unauthorized access. 122 . Of particular importance is the need to manage identities and entitlements in the cloud. and we have several small workloads. Ideally. Performing Maintenance and Upgrades Maintenance and upgrades of applications will have to be coordinated with the cloud service provider. Similarly. security concern is addressed by the cloud service provider.The Definitive Guide to Cloud Computing Dan Sullivan Managing Workload Providing services through the cloud will require us to think of jobs and workloads in ways that we do not necessarily need to when we have full control of dedicated servers. for example. If. If private information is stored in the cloud. storage. Direct access to the private data via the persistent storage API will also have to be blocked through authentication mechanisms and access control lists (ACLs) or other authorization control. our cloud charges a minimum of 1 hour of server time for each instance. but customizations might be the responsibility of the application owner. we should run those in tandem on a single virtual server rather than run them on different servers each incurring the minimum charge. they can determine their own upgrade schedule (within broader company policies. we will want to maximize server utilization when we run our jobs while ensuring jobs finish in whatever time window required. patching and other maintenance decisions will have to be coordinated with the cloud provider. In the cloud. When departments or projects manage their own servers. applications are delivered through virtual machine images maintained in the centrally managed image catalog. anyway). We have seen the overlap in concerns between both parties for issues such as image management. Maintaining Security Fundamental security considerations continue to persist in the cloud. we must consider application‐level security issues such as vulnerability scanning.
running a cloud does not necessarily entitle one to run as many instances of a commercial off‐the‐shelf product as one would like—cloud service consumers cannot not be expected to monitor the number of copies of licensed software running in the cloud or to know licensing details. which is necessary for tracking who uses which services and for how long. and others related to service monitoring and availability. provide the higher‐level management services necessary. Reliability. adapting IT operations to cloud architectures and topics. storage services. especially when running a private cloud. In addition. Summary Cloud services can be provided with a number of architectures. which are services that allow non‐IT professionals to deploy cloud services as needed Performance management. 123 . thus license management systems are needed to ensure compliance • • Support services such as these. performance. this is essential for proper cost allocations or billing for cloud services License management services are important for compliance. cloud operations management. and network services all come into consideration at the most fundamental levels. and management reporting are recurring themes when considering those three core services. which provides additional management reporting and monitoring services that allow cloud providers to understand detailed operations in the cloud as well as plan for longer‐term management issues Usage accounting.The Definitive Guide to Cloud Computing Dan Sullivan Service management includes additional services necessary for managing the business of providing and using a cloud. These include: • • Provisioning. Issues related to providing computing services. and service management must be examined as businesses choose the right cloud architecture for their situations. and a wide range of factors need to be considered when choosing to deploy a cloud.
and meets a wide range of business needs. much depends on how well they prepare for the adoption of cloud computing. Cloud computing is not a universal panacea and some business processes are better delivered by other approaches. Assessing Readiness for Cloud Computing The ancient Greek aphorism "know thy self" is surprisingly relevant to planning for cloud computing. The planning process consists of several steps: • • • • • • Assessing readiness for cloud computing Aligning business strategy with cloud computing services Preparing to manage cloud services Planning for centralized resources Committing to service level agreements (SLAs) Meeting compliance requirements The chapter concludes with a pre‐implementation checklist to help manage your own planning phase. Not all businesses will benefit equally from cloud computing.The Definitive Guide to Cloud Computing Dan Sullivan Chapter 7: Roadmap to Cloud Computing: The Planning Phase The benefits of cloud computing are well established: This model of service delivery is efficient. scales well. These benefits are maximized when business drivers. infrastructure. and policies are properly aligned to take advantage of the clouds method of delivery services. The purpose of this chapter is to outline a planning process that will help maximize the benefits of cloud computing. The first step in the planning process is to assess where the organization stands with respect to • • • Web application architecture Self‐management of compute and storage services Standard platforms and application stacks 124 .
could be exchanged for a different form of the component. such as: • • • • • Level of centralization Coupling of components Accessibility of components Ability to execute multiple instances Platform independence We need to consider how existing applications are designed with respect to each of these to understand how well those applications are adapted to cloud infrastructure. For example. complex batch‐oriented mainframe applications that have developed over years to incorporate many functions. Centralized applications range from small utilities to large enterprise‐scale applications. Web Application Architecture Applications are designed using a variety of design principles that are roughly grouped into what we call application architectures. These applications are at one extreme of the centralization spectrum. in fact. we will briefly describe each of these characteristics. Levels of Centralization An application may be centralized with all application code executing on a single machine. which perform the bulk of computing and storage operations. The middle ground of centralization is typified by client/server applications. and under the control of a single component. is largely controlled by a single control module and executes on a single machine. but first. and client devices that are responsible for user interactions. the work performed by an application is divided between servers. At this stage of the planning process. This is the planning process and the point of the assessment stage is to understand what resources are in place when we begin the move to cloud computing. A simple example of an application employing this approach is an order entry system consisting of a . with some effort.Net user interface running on a Windows desktop and a SQL Server database. Also in the most centralized application category. although divided into sub‐modules. These architectures vary in terms of a number of characteristics. those with characteristics most closely aligned to Web application architectures are best suited for the cloud. it is not necessary to have all three in place at ideal levels. The information gathered in this process will help to guide later planning and design efforts. This is not a problem. The client and the server components are fairly tightly coupled but they execute on separate devices and the components. In this application architecture.The Definitive Guide to Cloud Computing Dan Sullivan Each of these three areas is relevant to the delivery of cloud services. the SQL Server database could be replaced with an Oracle database with little impact on the client. a simple text editor can be realized with a single executable that runs a simple accept input‐process input‐generate output loop. most organizations not already supporting a cloud infrastructure will likely not have fully deployed and standardized around these three areas. A billing system for a telecommunications company. For example. we have large. for example. in a single process. 125 . As we will see. may have millions of lines of code that.
such as a service. For example. and user interaction services provided by a Web server. compute services provided by a Java application server. a procedure for calculating the shipping costs of an order may be part of a larger order entry program that calls that procedure at specific points in the execution of the order entry process with a data structure specific to that program. may be tightly coupled with other components. user management provided by an LDAP server. 126 . Loosely coupled components can execute in more autonomous ways. Web application architectures take advantage of decentralized applications to combine services. or procedure. Applications built on loosely coupled components work well in cloud architectures because the number of instances can be adjusted to meet demand and the services they provide are available to other applications running in the cloud. Others. This is an example of a tightly coupled set of components. a component must: • • • • Be programmatically discoverable so that other components can find it Exchange input in well‐generalized formats. and they exchange input and output in ways that support a broad array of calling applications. To be accessible. Coupling of Components The components of an application. A typical Web application may require persistent data storage provided by a relational database. they may be executed on the behalf of multiple calling programs.The Definitive Guide to Cloud Computing Dan Sullivan Decentralized applications execute multiple processes over multiple devices. are met by using scalable architectures such as compute clouds. such as XML Respect authentication and authorization requirements Maintain reasonable response rates under varying loads Web application architectures are built on accessible components using standards such as SOAP and WS‐Security to meet some of these requirements. module. Accessibility of Components Accessible components are those that are available to different services. Decentralized applications are especially well suited for cloud architectures because services can be run on virtual servers as needed and new services can be easily added without disrupting the loose coupling between services or requiring one to provision additional dedicated hardware. They may run on different servers. such as the ability to maintain reasonable response rates.
Services are decoupled so that requirements define how data is exchanged between those services but not how the services execute. A monolithic application. If the application cannot finish processing in the time window allotted to it. After all. Applications that do not use this model can still benefit from the management and cost benefits of using cloud services. but Web application architectures. built on decentralized. Applications that use this approach are well suited to the cloud. loosely coupled components that are accessible to other service components and can scale to meet loads placed on them. Platform Independence Another characteristic of Web applications is that services are not required to run on a single type of platform. Applications that are well suited to the cloud do not require that only a single instance of the program execute at any one time. the application manager could not simply start another instance of the program on a different server and finish in half the time. The more decentralized and loosely coupled the application. may assume that it can lock a file of customer data for exclusive use preventing other processes from operating on that resource. A service that needs to retrieve information about a user could just as easily do so by calling an LDAP service running on a Linux platform as by calling Active Directory (AD) running on a Windows server. Older applications may not have been designed with this characteristic in mind. 127 . generally do not have these problems. This combination of characteristics is seen in the service bus model that uses message passing and service abstraction. why couldn't one run multiple instances of an application? The answer: You couldn't run multiple instances when components are tightly coupled and exclusive use of a resource is required. loosely coupled components. for example. the greater the potential benefits. Web application architectures are characterized by decentralized.The Definitive Guide to Cloud Computing Dan Sullivan Ability to Execute Multiple Instances The ability to execute multiple instances might seem an odd requirement at first.
From an assessment perspective. For example.1: Web applications that utilize a service bus model are well suited to executing in the cloud. Even without a formal service bus. the common 3‐tier architecture that Figure 7. a business should try to determine how closely existing applications use a Web application architecture. 128 . other application architectures can exhibit the characteristics that fit well with cloud computing.The Definitive Guide to Cloud Computing Dan Sullivan Figure 7.2 shows has many of the characteristics previously described.
This could take minutes to days depending on the backlog in IT support. Another factor to consider when assessing readiness for cloud computing is support for self‐management of resources. and platform independence.2: The 3tier architecture also exhibits decentralization.The Definitive Guide to Cloud Computing Dan Sullivan Figure 7. The same problem could occur in the cloud if cloud consumers were not able to rapidly respond to changes in demand. As we have discussed in previous chapters. 129 . The potential delays can lead to application managers allocating more storage than needed simply to avoid any possible risk of running out of space and not getting additional storage in time. It is not uncommon for users of storage arrays to have to submit a ticket to IT support to have additional disk space allocated to their dedicated servers. This is true for both computing and storage resources. loose coupling. one of the inefficiencies in dedicating servers to a single application is that such servers have to be configured for peak capacity and this often leads to underutilization during non‐peak periods. Self‐Management of Compute and Storage Resources The efficient allocation of compute and storage resources requires the ability to start and stop services on demand in response to changing conditions.
possibly 20% of all the platforms and stacks that are currently in use in a business. we want to minimize the number of distinct application stacks we support in the cloud but we also want to maximize the number of applications that can be supported in the cloud. 130 . Adding application stacks should increase the ability to support either a significant number of general applications or targeted mission‐critical applications that would benefit from running in the cloud. Standard Platforms and Application Stacks Standardizing on a limited number of operating system (OS) platforms and application stacks can ease the management of a compute/storage cloud. First. Those compose the "80%" side of the 80/20 rule. application managers would be able to allocate compute and storage resources as needed. This certainly will not prevent a business from moving to cloud computing but it will require that such a system be put in place. It is likely that many of the applications run on similar sets of OS and application stack. the effort required to migrate between those should be fairly low in most cases. directory servers. When evaluating compute and storage service self‐management software. In many cases. Determining Required Platforms and Application Stacks For planning purposes. Web servers. one can derive a list of distinct combinations of platforms and application stacks. is not to redesign existing applications but to leverage the benefits of the cloud. self‐management software is not in place prior to adopting cloud computing. This calls for something of a balancing act. and other core components. consider the following factors: • • • • • • Ease of use Management reporting for cloud consumers Integration with accounting and billing systems for chargeback purposes Adequate authentication and authorization Job scheduling features or integration with existing job scheduling systems Ability to scale to the number of cloud consumers Another factor that will influence ease of management is the ability to standardize on platforms and application stacks. compile an inventory of applications including OSs. application servers. For the remaining applications. An application that depends on a Windows server platform or on components that only run on Windows platforms would be significantly more difficult to port to a Red Hat platform. Many organizations may find something akin to an 80/20 rule applies to them: 80% of application needs can be met with a relatively small number of platforms and application stacks. however. if many applications are running on a Red Hat version of Linux while a handful are running on SUSE versions. assess the level of difficulty in transitioning from the existing combination of OS and application stack. For example.The Definitive Guide to Cloud Computing Dan Sullivan Ideally. With that inventory. The goal in moving to a cloud architecture.
Net applications and servers Commonly used application servers. For example. with Linux. custom needs. such as: • • • LAMP stack. there are services and policies that should be standardized across platforms in the cloud. with . these systems would be used to: • • Determine how users or agents are authenticated to self‐service applications used to manage cloud services Determine limits on cloud consumers.The Definitive Guide to Cloud Computing Dan Sullivan Organizations that already have large portfolios of Web applications will likely find that they can address many of their requirements with a small number of different application stacks.3: Relative distribution of platform/stack needs that can be met by a small set of commonly used stacks. such as the maximum number of instances a user can start at one time or the length of time a single instance can be running a single virtual machine Allocate charges for cloud services to the proper department or billing code • 131 . and Perl/Python/PHP Windows stack. Required Support Services The cloud should provide identity management services such as authentication and authorization services. These are necessary to properly administer a cloud. such as Java application servers and Java portals Regardless of the combination of application components and OSs. Figure 7. MySQL. and custom platform/stacks for single. Apache. specialized stacks for less common requirements.
such as OS vulnerabilities. but IT support staff may be most familiar with lower‐level details. Ruby is an interpreted programming language akin to Perl and Python. This stage of planning requires an assessment of which applications will fit well with the cloud. The company may have standardized on Java or . The most compelling is that cloud consumers have access to exactly what they need. who is responsible for patching and maintaining customized virtual machine images? The creators know the components and applications best. Ruby must be available on a server to execute a Ruby application. during the assessment stage. those using Web application architectures. reducing the need for application‐specific identity management systems. such as a service bus architecture or a multi‐tiered application stack are well suited for the cloud. Once those applications are in place in the cloud. we consider more business‐oriented aspects. The disadvantage of allowing customized virtual machine instances is that they are more difficult to manage. one should identify the standard platforms and application stacks that are needed in the cloud. Customization and Specialized Requirements Another issue to consider around standardizing platforms and application stacks is the need for specialized versions of cloud‐provided standards. how would it be dealt with? Will users have the knowledge and time to test patches before deploying in production? Will metadata about the contents of custom images be kept up to date? Will this task duplicate efforts already carried out by cloud providers? We are starting to see the potential for the kind of inefficiency that drives up IT costs in non‐cloud environments. if a patch were to break the application.The Definitive Guide to Cloud Computing Dan Sullivan The same authentication and authorization services could be made available to applications running in the cloud. Finally. Self‐management services are essential to realizing the efficiencies of the cloud. There is no need to port applications to other platforms or find alternative solutions that run on standard platforms. 132 . In the next stage.Net for all application development but a department needs to host a third‐party application developed in Ruby. cloud consumers will want precise control over how they execute and the storage they use. the department may want to create a specialized virtual machine image to meet their needs. The first stage of planning considered primarily technical aspects of delivering services in from a cloud. Also. If this language is not part of the standard cloud offerings. The benefits of the cloud should not be undermined by unnecessary management overhead. There are advantages to allowing customized combinations of OSs and applications stacks. For example. Assessing readiness for moving to a cloud architecture is a critical first step in the planning process.
inquiries. thousands. such as generating invoices. As part of the planning process. or even more applications executing business processes. Some of these are transaction‐processing systems that provide high‐volume. we need to understand what types of jobs can run in the cloud (that was addressed in the previous section) and how to run them efficiently. reviewing inventory levels. or a broad array of other narrowly focused business activities. they might need: • • • • To start and finish executing within a particular time period To wait for another job to complete before it can begin To limit the functionality of some services. Still others are extracting data from one application. There is a wide array of different types of applications that are needed to keep an enterprise functioning. and moving it into a data warehouse.The Definitive Guide to Cloud Computing Dan Sullivan Aligning Business Strategy with Cloud Computing Services Clouds are deployed to deliver services and services are established to meet business requirements. To ensure cloud services are deployed in a way that is aligned with business strategy. write‐locking a file to perform a backup To provision a significant number of servers for a short period of time for a compute‐intensive operation Any cloud will have finite resources. transforming the data into a format suitable for analysis. Other applications are performing batch operations. Workload Analysis Right now in your business there are hundreds. These different types of applications have different requirements and constraints that must be considered when moving them to the cloud. rapid processing of orders. 133 . reservations. For example. for example. we should consider existing workloads and their corresponding value metrics. or performing data quality control checks on databases.
but in the planning stages. To do so. To assess the value of cloud computing.The Definitive Guide to Cloud Computing Dan Sullivan Figure 7. We want to deploy sufficient cloud infrastructure to avoid periods when cloud consumers want to run more jobs than there is capacity for (over‐utilization) at the same time we do not want extended periods of time when servers are idle (under‐utilization). we can look at existing workloads and take into account: • • • How often jobs execute on dedicated servers The level of utilization of those servers Time constraints on when those jobs execute Once again we are faced with a balancing act. ideally. Cloud consumers are the ones who will decide when to start and stop jobs and how many virtual servers to provision for particular tasks.4: The combination of workloads running in the cloud determines overall utilization at any point in time. periods of underutilization and over utilization are minimized. we can consider more targeted measures such as the value relative to hardware and software investments and relative to labor costs. Value Metrics Developing a precise and generally accepted ROI function for any IT investment is difficult at best. 134 . This brings us to the second aspect of business alignment: value metrics. we will want to ensure there is sufficient capacity.
the cost of licensing and hardware can be divided among multiple users. Repurposing When first deploying a cloud. Large numbers of servers all built using the same. and a third user runs the application for 10 hours a day. Labor Value The cost of labor in the cloud model is lower than dedicated server models for a couple of reasons. 135 . Prorating the cost of licensing and maintenance over 18 hours of daily utilization lowers the cost for all three users. you might want to repurpose hardware that had been dedicated to applications that will now run in the cloud. First. we have to balance the benefits of standardizing on hardware with the cost savings of repurposing hardware. another for 6 hours a day. especially the user who only needs 2 hours of application services per day. Once again. the hardware and software costs are the same when running that application on a dedicated server. One option is to repurpose non‐standard hardware but replace it with standard equipment as it fails or no longer meets functional requirements. or very similar. There is less overhead to manage inventory and fewer chances for errors in configuration if all servers use the same type of components. They include: • • • • OS costs Application software licensing and maintenance costs Database management licensing and maintenance costs Hardware procurement and maintenance costs The costs are relatively fixed. one department might run an application for 2 hours a day. in the cloud. so it does not matter whether you run your application 24 hours a day or 1 hour a day. there is an opportunity to standardize hardware. If a hard drive fails in a server. Some of this hardware may not match the cloud's hardware standard.The Definitive Guide to Cloud Computing Dan Sullivan Hardware and Software Values We will begin with hardware and software value measures by considering the constituent costs of running an application on a set of dedicated servers. The cost model of a cloud is different. Standardizing vs. components are easier to maintain. In a cloud model. replace it with a spare that would work just as well in any other server. For example.
with self‐service management. if a vulnerability is discovered in an OS. we have considered readiness of an organization to move to a cloud architecture in terms of technical issues. IT support staff that had been dedicated to responding to basic server support (for example. private clouds may be more cost effective as well. Businesses will still need to manage their workloads. Role of Private. public. For example. The cloud infrastructure will require IT support services that can be provided more efficiently in the cloud than with servers dedicated to particular applications. This reduces the risk that an outside party will gain access to private or confidential data. A public cloud is one that is managed by a third party that provides services to its customers. we are better able to align business requirements in a cost‐effective way with cloud services. Public. at least with respect to basic cloud services. We now turn our attention to a few issues related to longer‐ term management of cloud services. allocating disk storage. We have also examined the alignment of business strategy with cloud services in terms of workload analysis and value metrics. installing software. and running backups) can now be dedicated to higher‐value tasks. public. such as the use of Web application architectures and standardization on platforms and application stacks. 136 . and deploy those images to the service catalog. Compare that task with the patching of hundreds of servers across the organization.The Definitive Guide to Cloud Computing Dan Sullivan Second. Depending on the implementation and management details. The organization controls all aspects of cloud implementation. as we shall see. and so on. For example. and Hybrid Cloud Services There are three broad modes of delivery for cloud services: private. These are: • • • The role of private. lowering the initial costs. The primary advantage is low startup costs on the part of customers and minimal management overhead. management. allocate chargebacks. One of the most significant advantages of this approach is that data never leaves the control of its owner. By analyzing workloads and calculating initial value measure in the planning process. a business may have significant investment in servers that can be redeployed in the cloud. Preparing to Manage Cloud Services Up to this point in the planning process. cloud consumers can manage their own applications and workloads. and governance. and hybrid. regenerate virtual machine images. a single administrator can patch the OS. and hybrid cloud services Planning for growth Long‐term management issues These issues. A private cloud is deployed and managed by an organization for its own internal use. are strongly influenced by demand for cloud services.
137 .5: The cost of adding and maintaining additional cloud resources eventually reaches a point where the costs outweigh the benefits. at which the benefit of adding servers to a private cloud is not sufficient to offset the costs of adding them.The Definitive Guide to Cloud Computing Dan Sullivan Choosing between public and private cloud implementations is not an all‐or‐nothing proposition. storage. and ancillary equipment as needs demand or by adopting a hybrid cloud approach. have emerged as a third alternative. Planning for Growth If successful. Figure 7. a cloud is likely to grow both in terms of underlying infrastructure and in terms of the number of services provided by the cloud. Hybrid clouds. growth in infrastructure can occur internally by adding servers. There may be a point. At this point. at the end of the month when accounts are closed and data warehouses and data marts are updated and many reports are generated) or they may be more unpredictable periods of high demand. Consider the economic benefits. or the combination of private and public implementations to run business services. however. For example. These peaks may be regular short periods (for example. the distribution of workloads may entail a number of peak periods where demand exceeds the capacity of the private cloud. In the case of private clouds. a hybrid cloud approach may be the most costeffective option.
may be introduced to more evenly distribute the workload in cases where there are periods of high and low demand. the cloud allocates resources to the highest bidder. for instance. Peak pricing could be instituted during high‐demand periods and lower prices during low‐demand periods. such as long‐term cloud consumers who need continuously running servers.The Definitive Guide to Cloud Computing Dan Sullivan Growth in services will put a different kind of management burden on cloud providers. users who will take advantage of the cloud for occasional needs. In particular. cloud providers will need to plan for: • • • • Expansion in the number of OSs and application stacks that may be supported Growing demand for custom virtual machine images to accommodate specialized requirements A growing base of cloud consumers with widely different needs Emerging categories of users. 138 .6: Using public cloud services in a hybrid cloud configuration during peak demand periods may be the most costeffective way of meeting the demand for peak capacity. Another option is to use an auction model in which cloud consumers specify the price they are willing to pay for a resource. Figure 7. and so on until all resources are allocated. These different factors will help shape management and pricing policies. then the next lower bidder. or spot users who will use the cloud only during off‐peak hours if the cost is lower at those times. users with intermittent but regularly scheduled needs for servers. A market pricing model.
During the planning stage. possibly with multiple sites for a private cloud or with the use of a hybrid cloud approach Managing identity. Standardizing to Reduce Complexity Standardization reduces complexity. for example with the greater use of instrumentation and data collection These are broad issues that will continue to evolve over time. In addition to these. an important point to remember is that the policies and methods used in the early days of cloud adoption may not be the best option in later stages. it is important. Following past practices because "that is the way we've always done it" is not always a recipe for success. but the degree of standardization required to realize benefits is not as great as it is with cloud computing. This can come in several forms: • • • Standardizing to reduce complexity Streamlining service management Virtualizing physical resources These various forms of centralization are important individually. there are several long‐term issues and responsibilities that warrant more detailed consideration. and governance. management. significant rise in demands. authentication. These include both service and infrastructure issues: • • • • • • Maintaining the security and integrity of virtual machine images Monitoring. detecting. When we use the "one server for one application" approach to delivering services. but they also reinforce and support the realization of each other. 139 . it is important to begin formulating policies and practices that support centralization.The Definitive Guide to Cloud Computing Dan Sullivan There are many ways to manage and price services. and blocking unauthorized uses of the cloud Planning for high availability and disaster recovery. That is not to stay standardization is unimportant. there is less need for standardization than in cloud models. and authorization mechanisms Handling physical configuration of the cloud and power consumption Acknowledging the potential for rapid. especially in the cloud. it is important to consider some of the long‐ term management issues that cloud providers will face. Long‐Term Management Issues In the planning stages for adopting a cloud. Planning for Centralizing Resources Cloud computing gains many of its advantages from centralizing resources.
Streamline Service Management One of the benefits of centralization is that by delivering services at large scales. In the previous example about data mart reporting. The result was additional complexity with no additional benefit. service management should include: • • Support for discovering services provided in the cloud through detailed and up‐to‐ date metadata about services Virtual machine images that are designed to support services. and the group functions well with it. The department had hired an analyst who had worked with open source reporting tools in the past and persuaded the department manager to use those tools as well even though the business had standardized on a commercial tool suite.The Definitive Guide to Cloud Computing Dan Sullivan Take for example a sales department that runs a small data mart. Once requirements are met. Similarly. preparation. Standardization is a key method of reducing complexity. adding components adds to complexity—that is. and not just OSs and application stacks. Centralized IT management would be responsible for deploying and maintaining the image. and delivery of those products. In particular. The goal of standardization is to meet all functional requirements with a minimal set of computing components. supported application. a non‐standard system was used when the enterprise standard solution would have worked. the number of interacting components that need to be maintained and adapted to function with other components—without adding to the goal of meeting requirements. the fact that hundreds or thousands of users will repeatedly invoke the same standardized set of services demands attention to streamlining and optimizing the delivery and management of those services. As it is in the catalog. A fast food chain that serves millions of sandwiches a year will optimize every aspect of the production. it pays to invest in optimizing those services. other users might make use of it. In order to streamline service management. such as Linux with a statistical analysis package installed Management reporting that allows cloud consumers to track and optimize their own use of cloud resources • 140 . What started as an isolated instance of using non‐standard software slowly shifts to becoming an institutionalized. (We will ignore the security implications of this decision for the moment). Now picture this application moving to the cloud. such as report generation. we need applications in place that reduce the manual labor and complexity of workflows required to implement management processes. The user base might grow to the point that IT must spend significant time to learn the tool in order to provide support. Such situations should be avoided when deploying a cloud. A virtual machine image would have to be created and maintained in the service catalog of the cloud. The department is responsible for building and maintaining its data mart. Centralized IT is not responsible for maintaining sales' department's system and does not object to it.
but the primary concern is on the business commitments cloud providers make to their customers. also require attention to business considerations. cloud SLAs may be more general and apply to capacity commitments. Virtual machine instances in the cloud. Computing and storage clouds hide many of the implementation details that go into building and maintaining a large IT infrastructure. greater control.The Definitive Guide to Cloud Computing • • Dan Sullivan Ability to provide timely support for cloud consumers in cases where there are problems executing jobs in the cloud Utilization analysis reports to give those responsible for managing cloud services the information they need to detect trends and analyze varying patterns of resource utilization One of the factors that supports the ability to streamline service management is the ability to virtualize cloud infrastructure. Scaling virtualization to a large number of servers requires management software that can manage multiple hypervisor clients from a single console. This is why we have SLAs. Committing to SLAs Business managers may look at cloud services and find the lower costs. the ability to virtualize computing and storage services are at the foundation of the efficiencies provided by the cloud model. Storage services also need to be virtualized so that they appear to cloud consumers to be a single storage device. storage infrastructure. These reasons are often not enough. should be able to address storage space on the cloud SAN(s) without having to manage implementation details. Setting up a set of virtual machines on a single server is straightforward: install a hypervisor and create virtual machine instances based on OS(s) of choice. and potential for scaling business processes compelling reasons to use cloud services. network infrastructure. The key physical resources that should be virtualized are servers and storage. SLAs are standard in IT. and availability and recovery management. Virtualizing Physical Resources The final aspect of centralizing resources we will consider is the need to virtualize physical resources. the same management console that is used to control servers in the cloud will support management and administration of storage resources. for example. It is not sufficient for a cloud to work well today. though. 141 . These SLAs are closely coupled to the infrastructure of the cloud. and it is no surprise that they are used with cloud services. however. Ideally. and virtualizing physical resources. Those same users. Rather than focus just on the availability of a specific application. it needs to work well for as long as users need it. cloud providers enable the technical resources needed by users to leverage cloud services. By standardizing services. streamlining service management. As we have encountered repeatedly within our discussion of cloud computing.
Service commitments will be limited by the network capacity of Internet service providers (ISPs) and the ability to distribute networking load across multiple ISPs. if any Availability commitments. Several factors should be considered when making capacity commitments: • • • • • The total infrastructure planned for a private cloud The ability to acquire additional resources (compute and storage) as needed through a hybrid cloud Changes in pricing models if hybrid resources are used A commitment to the percent of time the capacity will be available Length of time the capacity will be available without interruption once the capacity is provisioned The workload analysis performed earlier in the planning process can help to understand the capacity commitments a cloud provider can make given a particular number of servers and storage capacity. by combining network services from multiple providers. 142 . These can significantly reduce the total amount of storage available for direct use by cloud consumers. including percent of time storage services will be available Throughput commitments When considering the amount of storage available for use. Network Infrastructure Network service commitments are especially important when there are high levels of data exchange in and out of the cloud. however. Storage Infrastructure Storage SLAs take into account several factors: • • • • Amount of storage available for use Backup services. take into account the need for redundant storage to improve performance and availability.The Definitive Guide to Cloud Computing Dan Sullivan Capacity Commitments A capacity commitment in an SLA outlines the number and types of server capacity that will be available for use when the cloud consumer attempts to use them. Cloud service providers are limited by the service level commitment they receive from their ISPs. a cloud provider can improve total throughput and availability.
The Definitive Guide to Cloud Computing Dan Sullivan Availability and Recovery Management Another popular topic for SLAs is recovery management. one must often be able to demonstrate one is in compliance. Again. such as routine vulnerability scanning. Private clouds retain data within corporate firewalls where it will be subject to internal controls. The service can be started again on another server. if data moves from a dedicated file server to cloud storage. Compliance Requirements and Cloud Services Compliance requirements tend to focus on preserving the integrity of data. and protecting the privacy of confidential information. that when a server fails and another is started in its place. existing procedures might need to be modified to accommodate reporting on cloud procedures that support compliance. 143 . One of the greatest impediments to adopting public cloud computing is concern about protecting the integrity and confidentiality of data once it leaves the corporate‐controlled network. The redundancy of servers in the cloud ensures that the failure of a single server in the cloud will not disrupt an operation. a record may be logged indicating local data has been overwritten to prevent the next user from scanning local storage for residual data. the recovery point would be earlier. all data written by it should be overwritten. Authorizations assigned to users for non‐cloud resources should be respected in the cloud. the same restrictions on access should apply. will have to be adapted to scan machine images in the service catalog rather than just instances running at a particular point in time on a given set of servers • Reporting is another essential part of compliance. One must account for the fact. For example. but the cloud introduces additional factors that should be considered: • • Applications running in a virtual machine might write data to local disks. For example. When the virtual machine shuts down. another instance of the application can recover from the last point at which state information was written to the disk. A final set of issues that falls under the penumbra of business drivers is compliance requirements. If the application depends on maintaining state information in memory. Practices employed as part of compliance efforts. It is not sufficient to be in compliance. This may be true for the most part. cloud providers may be able to commit to high levels of availability in terms of having servers available to run applications. If the application writes state information to cloud storage. From a service level perspective. especially financial data. there may be data loss depending on how the application is written. each time a virtual machine instance is shut down. though. The assumption behind this reasoning is that governance procedures that protect data in non‐ cloud infrastructure are sufficient to protect the same data in the cloud.
public. In addition. Pre‐Implementation Checklist Assessing Readiness for Cloud Computing Determine whether applications are designed to use a Web application architecture. hardware. a pre‐implementation checklist is provided that summarizes the key points of this chapter.The Definitive Guide to Cloud Computing Dan Sullivan Summary Planning for cloud services is a multifaceted process that begins with assessing readiness for the cloud and aligning business strategy with cloud computing services. and software Understand the roles of private. service bus architecture. It also requires preparation for managing cloud services and planning for centralized resources. and hybrid clouds and their utility for business requirements Plan for growth in demands for services Assess long‐term management issues Perform capacity planning with respect to service level commitments Analyze capacity of network infrastructure Analyze capacity of storage infrastructure Formulate reasonable commitments with respect to availability and recovery management Determine security requirements for preserving the integrity and confidentiality of data Adapt reporting requirements to address compliance implementation issues introduced by the cloud Aligning Business Strategy with Cloud Computing Services Preparing to Manage Cloud Service Committing to SLAs Meeting Compliance Requirements 144 . such as SLAs and support for compliance efforts. or n‐tier architecture Assess ability to provide for self‐service management of computing and storage services Standardize on platforms and application stacks Analyze workloads Determine value metrics with respect to labor. To facilitate the planning process. it entails a number of business‐oriented concerns.
aligning business processes with cloud services. The first step in the cloud adoption process is to develop a comprehensive plan that begins with assessing readiness for cloud computing. but the implementation details are more complex in the case of private cloud computing. 145 . we are often required to maintain existing services. By definition. we shift focus from planning onto the actual implementation of the plan. The structure of the discussion is divided into five core subtopics: • • • • • Establishing a private cloud Transitioning compute and storage services to a cloud Completing a post‐implementation checklist Managing cloud services Extending a private cloud with public services By the end of the chapter. This chapter will address how to implement a private cloud and will include discussion of hybrid and public cloud issues as well. at the same time. planning for centralized resources.The Definitive Guide to Cloud Computing Dan Sullivan Chapter 8: Roadmap to Cloud Computing: The Implementation Phase One of the most challenging IT tasks is to implement a new systems architecture. we are introducing a new way of delivering services. in this chapter. We described this first step in detail in the previous chapter. we will have outlined some of the fundamental issues that should be considered during the implementation phase in order to begin deploying cloud services within an organization. It is analogous to repairing your car while driving it. and committing to service level agreements (SLAs). Many planning issues are common to both public and private clouds.
146 . space required for an organized cable distribution system must also be taken into account when sizing the data center. such as the number of servers and amount of network equipment and how they are deployed and configured Environmental concerns. Servers are often rack‐mounted in industry‐standard 19‐inch rack cabinets.The Definitive Guide to Cloud Computing Dan Sullivan Establishing a Private Cloud A private cloud begins with the deployment of hardware. we have often discussed the business services. For more guidance on configuring a data center. Data centers should be sized according to initial space requirements as well as for foreseeable growth. such as space. Data Center Standards Standards for configuring data centers have been established by the Telecommunications Industry Association (TIA). There must be adequate space within the data centers for the server units. software architecture issues. Deploying Hardware for a Private Cloud Many of the hardware issues we have to address in a private cloud are familiar to those with data center experience. and cooling Redundancy to prevent single points of failure Servers and Network Equipment Servers in a private cloud are housed in one or more data centers. the data center equipment should be organized in a logical fashion to support maintainability. These are typically configured to allow easy access to both the front and back of the cabinets. see the TIA‐942 Data Center Standards Overview by ADC. power. Throughout this book. Distances between components should be minimized in order to minimize cable lengths. and other logical design considerations. All of those logical choices ultimately depend on lower‐level services that in turn rely on an IT infrastructure that includes: • • • Private cloud hardware Networking Application stacks Deploying a cloud begins down in the infrastructure. networking. The number of servers in a cloud can grow incrementally quite easily but the physical space for housing them may not. They tend to cluster around • • • Server‐level issues. but more importantly. Cabling is run through racks to improve cable management. and software services.
Fire prevention equipment includes active controls such as smoke detectors. At mid‐levels. The generators are designed to supply power for longer periods of time. redundancy is built‐in to the components we deploy as single components. air conditioners. A second air conditioning unit is an example of the former. Key considerations are reliability and adequate supply of power. from dual power supplies in air conditioning units all the way up to duplicate data centers. can also be used to contain fires to one part of the data center. and fire suppression gaseous systems. Redundancy and Avoiding Single Points of Failure Redundancy is found at multiple levels in a data center. we incorporate redundant components or backup systems in a data center. access control badges. The physical integrity of the data center must be protected with access controls to prevent unauthorized access. sprinkler systems. Tips on Energy Efficiency for Data Centers See The Quick Start Guide to Increase Data Center Energy Efficiency by US General Services Administration and the US Department of Energy for tips on reducing the costs and environmental impact of operating a data center. especially: • • • • Power Cooling Fire prevention Physical security External power generators will typically supply electrical power to a data center. Humidity control is also a concern because too much moisture in the air can result in condensation on electrical equipment. a backup power system can be used. Uninterruptable power supplies can use batteries to supply power immediately in the case of a power failure while diesel generators are started. such as servers. To prevent a single point of failure in the power supply system. Cooling is another factor that must be taken into account when designing a data center for a private cloud. such as using outside air. and surveillance cameras are all used to protect data centers.The Definitive Guide to Cloud Computing Dan Sullivan Environmental Issues Servers and networking equipment depend on environmental infrastructure to keep functioning. are in use as well. an uninterruptable power supply is an example of the latter. and disk arrays. At the lowest level. 147 . Guards. Servers and other electrical equipment dissipate heat into the environment and the temperature in a data center will rise unless the center is cooled. Air conditioning is the common method for cooling but alternatives. such as firewalls. Passive controls.
Figure 8. that database will eventually be replicated to other data centers unless the problem is discovered in time. Multiple data centers with similar infrastructures can act as backups for each other. data needs to be replicated between data centers in a timely manner. the other data centers can carry the workload of the downed data center. we need to deploy sufficient networking resources to meet the demand generated by cloud computing. If an application error corrupts a database in one data center. 148 . In addition to compute and storage infrastructure. This is obviously a costly option but has a number of advantages. A backup would allow the business to recover from the data corruption. It should be noted that this process is not the same as backups. This kind of disaster recovery configuration requires a well‐defined plan before the disaster.1: Redundancy is used at multiple levels to avoid single points of failure that could shut down a single component or an entire business process. For example. We may do this any way to ensure high availability even without regard for disaster recovery situations. replication may not. If one data center is hit with a natural disaster. Data replication copies data and overwrites existing data in some cases.The Definitive Guide to Cloud Computing Dan Sullivan At the top level. if a disk array fails in one data center or network traffic to that data center is unusually high. Backups are copies of data at a point in time and preserved from some period of time. other data centers with the replicated data can respond to service requests for that data. we duplicate entire data centers. For example.
As with compute and storage hardware. They also contribute to high availability by enabling load balancing across network devices.The Definitive Guide to Cloud Computing Dan Sullivan Deploying Network Services for a Private Cloud Business services delivered through the cloud will determine network bandwidth. Even with redundant devices on the corporate network.2 depicts a fully redundant WAN. 149 .2. Figure 8. and reliability requirements. we still face a risk of losing network services on the internetwork between data centers and other corporate offices. This architecture can become cost prohibitive quite quickly. A fully redundant network requires two or more links between each interlinked network. Consider a private cloud that uses two data centers and supports WAN connections between the data centers and for corporate offices. Figure 8. we would need a total of 90 links. latency. If we increase the number of data centers to two and add four more corporate offices (10 endpoints). The number of links in a fully redundant network grows according to the formula: n(n ‐1) where n is the number of endpoints. redundant components such as routers and switches are important for avoiding a single point of failure. Providing redundant links over the wide area network (WAN) is an obvious solution but there is a significant drawback: cost. In this simple example of one data center and four corporate offices (five endpoints). there are a total of 20 WAN links. The network architecture selected for a private cloud will determine how those requirements are met.
management policies. If any single link fails. Figure 8. that Figure 8. and management reporting. Providing Application Stacks In addition to deploying hardware and networking services.3 depicts a network with 10 endpoints but uses only 18 WAN links. This requires support for at least three elements: cloud management services. and OSs that run as virtual machines within hypervisors. We have applications that run inside application servers that run inside an operating system (OS).3 shows an example of a mesh network that provides multiple routes between any two endpoints. Note. we need to provide for and manage application stacks within a private cloud.3: A mesh network architecture provides redundancy with fewer links than a fully redundant design. the endpoints can communicate using the other WAN link. This layered approach continues in the cloud with cloud management software that carries out basic cloud operations: • • • • Starting and stopping virtual machine instances Providing access to network storage systems from virtual machines running in the cloud Managing cloud storage services Tracking usage information for accounting and billing 150 .The Definitive Guide to Cloud Computing Dan Sullivan An alternative approach is to use a mesh design in which each endpoint in the WAN has links to two or more other endpoints. Figure 8. Cloud Management Services Cloud management services can be thought of as another layer in the software application stack.
The Definitive Guide to Cloud Computing Dan Sullivan Figure 8.4: The conventional application stack is extended in the cloud to include cloud management services below virtualization services. which is a repository of virtual machine images that may be run in the cloud Access controls on cloud services. Cloud management services must accommodate several types of needs: • • • • Clustering groups of servers to support high‐performance computing needs for tight coupling of applications running on different servers A service catalog. such as the ability to start and shut down instances or add images to the service catalog Storage abstractions for persistent storage after virtual machine instances are shut down 151 .
instead.5: Cloud management services include applications to allow users to provision their own virtual machines as needed without assistance from IT support personnel. and durations of use of virtual machines a single project can provision Access control policies with regard to provisioning virtual machines and storage allocations Backup services Limits on SLAs and the cost of different SLAs Data retention and data destruction policies Policies are in place to ensure cloud service consumers can plan their use of the cloud according to enterprise‐wide constraints. Policies also serve cloud providers who need to maintain compliance with internal requirements and SLAs as well as external regulations. Cloud Management Policies Cloud management policies specify how cloud resources are governed. types. a private cloud should assess current policies and make modifications as needed to accommodate: • • • • • Privileges and limits on the number. Computing cloud architectures evolved from earlier IT architectures.The Definitive Guide to Cloud Computing Dan Sullivan Figure 8. we have extensions to existing policies (for the most part). 152 . so there are not necessarily new types of polices. At minimum.
Network services are essential to delivering cloud services. user location. and so on.The Definitive Guide to Cloud Computing Dan Sullivan Cloud Management Reporting A system of reporting on cloud operations must also be in place early in the deployment phase. As the number of data centers and remote sites grows. Establishing a private cloud is a multistep process. Networks will have to be designed with enough redundancy to provide robust networking but not so much that the costs outweigh the benefits. Cloud service providers will need management reports that describe key performance indicators of the cloud: • • • • • • Server utilization Storage utilization Network bandwidth and latency Security incident reports Service support tickets Service catalog inventory and summary descriptions Ideally. the cost of point‐to‐point dedicated networks quickly becomes prohibitive. such as time. Typical reports in this category include: • • • • • Number and type of servers used and the duration of each use by job or project Amount of storage allocated by job or project CPU utilization rates Images and software used. such as redundancy and failover. especially if charge backs are applied for software licenses Summary reports on jobs scheduled and time required to complete jobs and total cost by job Cloud management reports should help cloud providers more efficiently deliver cloud services as well as help cloud consumers more efficiently support their business services and workflows. such as power. 153 . Hardware must be deployed with consideration for physical infrastructure. cooling. and physical security. Application stacks must also be deployed with particular attention to cloud management services. department or line of business. as well as architectural issues. and management reporting. these reports are available for aggregate measure across the enterprise as well as by important dimensions. data center. management policies. Cloud service consumers will also look for management reports but with an emphasis on managing their own use of the cloud.
There are several types of business drivers. In the case of a server running four OS instances but still has CPU cycles available. In a cloud. which would drive up the cost. Four lightweight services running on a high‐end server are better than one service but can still leave CPU cycles wasted. we need to formulate a plan. and applications in a private cloud. Utilization can improve if the server uses virtualization to run multiple guest OSs with different services. another instance can be added by the cloud management software. Of course. Prioritizing Based on Business Drivers Before we start redeploying servers and moving applications off their current host servers. but many business operations never fully utilize the capabilities of servers. (We described the reasons for this in detail throughout this book and will not repeat them here. There are several steps in the transition to a cloud infrastructure: • • • • • • Prioritizing steps based on business drivers Reallocating servers Deploying cloud‐enabling applications Testing and ensuring quality control Deploying management applications Migrating end user applications This list is roughly the order in which the steps are executed during the migration. Business Driver #1: Cost Clouds can deliver services more efficiently than can dedicated servers in many cases. typically make little demand on server resources. one could add another instance to a virtualized server without cloud management software but doing so would require an IT support person. collaboration. for example.The Definitive Guide to Cloud Computing Dan Sullivan Migrating Compute and Storage Services to a Private Cloud So far in this chapter we have discussed aspects of deploying hardware. Multi‐core processors running on servers with significant amounts of memory can support compute‐intensive operations. this problem is mitigated by adding virtual machines to servers as long as there are resources available to support another instance. That plan should be shaped by the business drivers that motivated the move to a cloud architecture in the first place. but even this may not fully utilize the server's capabilities.) A typical example of a lower‐cost cloud‐based delivery is when a single server is dedicated to an application that uses only a fraction of the computing resources of the server. We now turn our attention to a more detailed look at the sequence of events that are needed to establish such deployments. and content management. and they should all be considered when formulating the plan. 154 . Servers dedicated to file transfer. network services.
If a data warehouse must perform complex extraction. The secondary set of servers aggregate data by region. and load (ETL) operations every night. and they. These servers can then pipe their output to another set of servers that receive data based on some criteria. transformation. such as geographic location. can make use of multiple servers for relatively short periods of time. pipe their output to another server for the level of data aggregation. which perform record‐level transformations and data quality control checks. such as data warehouse ETL operations. in turn. Source systems can send their input data streams to multiple servers. Figure 8.The Definitive Guide to Cloud Computing Dan Sullivan Business Driver #2: Computing Resources Another major driver for utilizing a cloud is the ability to provision computing resources on demand. 155 .6: Many business processes. a cloud is an ideal way to do so.
we might determine that several dozen servers hosting Web servers. we need to ensure that services that are currently provided by servers continue to be available as needed. but those that are underutilized could be better utilized in the cloud. Xen. To do so. are less likely to benefit from flexible allocation. Business processes that use a server at fairly constant levels. 156 . Depending on the type of cloud management software. For example. Business processes that experience high variability in resource demand are good candidates for early migration to the cloud. Even once the order of redeployment is determined based on business drivers. or KVM. the next step is to configure software for the servers. such as those dedicated to transaction processing on a continuous stream of input. The servers will run virtual machine hypervisors and integrate with cloud‐level management software for deploying virtual machine images.The Definitive Guide to Cloud Computing Dan Sullivan During the prioritization step. we should itemize both business processes and servers and determine (1) how the business process would benefit from flexible server allocation and (2) the relative utilization of the server. perhaps in the cloud if some are already available or to virtual hosts on servers dedicated to the migration process Back up data from the current production servers and restore to the transitory server hosting the application Delete data and applications from the server and install virtualization a platform and any cloud‐specific applications Physically connect the server to the cloud network segments and attach the server to network storage If the applications running on the servers prior to reallocation will be running in the cloud. Reallocating Servers Reallocating servers is not as simple as it may sound at first. we need to: • • • • Migrate applications to other servers. Deploying Cloud‐Enabling Applications After servers are physically allocated to the cloud and configured to use cloud networking services and cloud storage. collaboration servers. and several other department‐level services will all be assigned to the cloud. such as VMware products. virtual machine images must be added to the service catalog to support those applications. small databases. servers might run different hypervisors. Servers that run at near capacity would be only marginally more productive in a cloud configuration.
monitoring server and network utilization. all data on local storage is deleted when a virtual machine instance is shut down After testing these individual elements of cloud functionality. The test plan should include several steps that ensure: • • • • • • Virtual machine hypervisors are installed and running correctly on all servers Virtual machine instances can be started and stopped as expected Cloud management software correctly starts specified machine images on the correct number of servers All servers can read and write from cloud storage LDAP or other directory services are in place and function correctly on all servers Security policies are implemented correctly. 157 . however. we also need to implement policies and procedures for basic operations. When the cloud infrastructure is in place and functioning properly. such as replicating data between data centers. we want to verify that: • • • • Virtual machine instances start and are available for use in an acceptable amount of time Read and write operations to cloud storage are performing as expected Large numbers of parallel operations. we also want to ensure that usage and accounting information is tracked correctly. the next step is to migrate end user applications to the cloud. such as starting instances or writing to storage. such as servers dedicated to collecting usage data and generating reports and data services. During performance testing. at least in theory. When it comes to performance. Deploying Management Applications As noted earlier. management applications are needed for both cloud providers and cloud consumers. The goal of this step is to test and exercise the cloud configuration before opening it for production work. we can move on to performance testing. and necessary controllers are deployed. such as startup and shutdown of virtual machine instances. there are costs associated with marginal improvements in performance. are performed in an acceptable amounts of time Network latency and bandwidth are sufficient to meet SLAs During testing. At this point. for example. servers are allocated. This type of testing should be driven by the SLAs we expect to support. and ensuring supporting operations. recording usage information for accounting purposes. more is always better. At this point.The Definitive Guide to Cloud Computing Dan Sullivan Testing and Quality Control Testing is an essential part of cloud deployment. These may both be hosted on cloud controller infrastructure. cloud storage is in place. is functioning as expected.
Building Virtual Machine Images Building virtual machine images is a straightforward task. There are different ways of storing data in the cloud. so we should review an application storage scheme before migrating it to the cloud. and so on. 158 . Migrating Data to Cloud Storage Migrating data to the cloud is another process that sounds simple but has some potential challenges. One option is to use block storage in which data is written to logical blocks on cloud storage. This information has to be migrated to the cloud infrastructure and adjusted as needed in the cloud. and privileges. we could store different versions so that the user can choose the appropriate one as needed. the maximum time those servers can run. Migrating Access Privileges to the Cloud Applications that run on dedicated servers often make use of LDAP directories or Active Directory (AD) to store and serve information about users. a Java application server may be configured differently if we expect heavy. Rather than expect the user to adjust configurations each time a virtual machine instance is created. resources. another option is to use a relational database management system (RDBMS) to manage data in the cloud. but we must be careful to analyze application dependencies to ensure all necessary supporting software is in place. Additional data may also be required. such as limits on the number of virtual instances a user may start at any one time. such as tablespace file placement. different configurations of an application may require different versions of supporting libraries. user AJones has read and write privilege to \\server1\directoryA) to the comparable location in the cloud storage. Also. Applications may have different configurations depending on how the application is used. and this could also warrant having multiple versions. or light use.The Definitive Guide to Cloud Computing Dan Sullivan Migrating End User Applications Migrating end user applications is a three‐step process: • • • Building virtual machine images with necessary application stacks Migrating data to cloud storage Migrating access control privileges and directory information to the cloud. For example. accounting information for charge backs. Some changes may be required in applications to make use of cloud block storage. so we may need to support several versions of similar images. moderate. Adjustments range from mapping access controls to specific servers and directories (for example. The second option has similar functionality to RDBMSs that run on dedicated servers but without having to manage some of the lower‐level storage issues.
fire suppression Is redundancy used for critical components. deploying management applications. physical security. Post‐Implementation Checklist Deploying Hardware for Private Cloud Deploying Network Services for Private Cloud Topic Area Notes Servers and network equipment Environmental issues Avoiding single points of failure Establish data center infrastructure Power. backups. deploying cloud‐enabling applications. data retention policies Cloud provider and cloud consumer reporting Cost drivers Which servers can be most efficiently redeployed in the cloud? Which business services require significant computing resources? Which processes need regular peak capacity significantly in excess of more common workloads? Compute drivers 159 . testing and quality control. systems. There are many steps to the process.The Definitive Guide to Cloud Computing Dan Sullivan Transitioning compute and storage services to the cloud is a multistep process that begins with prioritizing services to migrate to the cloud based on business drivers and moves through reallocating servers. the following post‐implementation checklist summarizes the key steps. and finally migrating end users applications. access controls. cooling. and data centers? Network capacity Is network bandwidth and latency sufficient for SLA? Are redundant routes implemented in a cost‐effective manner? Redundancy Deploying Application Stacks for Private Cloud Cloud management services Prioritizing Based on Business Drivers Policies Management reporting Provisioning virtual machines and storage Privileges.
The Definitive Guide to Cloud Computing Reallocating Servers Migrating applications Dan Sullivan Plan migration and switch over Consider how to synchronize data if existing application continues to run during migration Wipe existing data on server. infrastructure storage. physically move servers to data center Deploying Cloud‐ Enabling Applications Testing and Quality Control Backup data Initialize servers for cloud Physically connect servers to cloud Establish connections to other servers. and network Deploying hypervisors Server‐specific monitoring applications Install low‐level software for OS and virtual machine functions Enable server monitoring services Does the server function as expected with regard to starting and stopping virtual machine instances? Writing to and reading from cloud storage? Use network services? Do servers function as expected under significant loads? Test for both compute and I/O loads Build service catalog with images as needed to meet the full range of application requirements Copy application data to cloud and verify applications function properly with regard to cloud storage Update LDAP or other services in the cloud that store authentication and authorization data Server‐based functional testing Migrating End User Applications Performance testing Building virtual machine images Migrating data to cloud storage Migrating access control information 160 .
and supplier management. see http://www. our attention shifts to more operational and maintenance‐oriented considerations: • • • Service management integration with the cloud Usage tracking and accounting services Capacity planning These are business operations that likely existed well before cloud computing was introduced. Actually. so it is usually a matter of extending these business processes to function with the cloud. financial management. Throughout this book. but we will only consider: • • • • Service catalog management Service level management Availability management Service validation and release management There are other aspects of service management that are relevant to cloud computing but are outside the scope of this chapter. but that should not be construed as meaning cloud computing cannot be customer focused. There are different ways of implementing service management. ITIL v3 For more information about the ITIL framework and other service management issues. which advocates a broad and fairly structured approach to service management. these include risk management. Integrating Service Management with the Cloud Service management is a set of practices that orient IT operations around customers' needs and business processes rather than around technology. There are many elements in the ITIL framework and service management in general.itil‐officialsite. 161 .The Definitive Guide to Cloud Computing Dan Sullivan Managing Cloud Services After the transition period when infrastructure is migrated to a cloud configuration. One of the most formal and well‐known approaches is the IT Infrastructure Library (ITIL).asp.com/home/home. we have had a decidedly technology‐centric focus. cloud computing actually improves customer service and supports the objectives of service management. by streamlining the delivery of computing and storage services.
and it is important to distinguish them here. Before we go any further. In terms of service management. Business services are made available through the cloud when they are added to the cloud's service catalog repository. A service catalog in the service management sense is an abstract description of the set of services available from information technology providers. In this section. are part of the service catalog in the management sense of the term. will be met Availability of software packages in the service catalog repository The details of SLA metrics will be slightly different with a cloud. In the cloud.The Definitive Guide to Cloud Computing Dan Sullivan Service Catalog Management Service catalogs are sets of business and support services available from IT departments. 162 . and Quality of Service (QoS) metrics are usually associated with these requirements. it should be noted that the term "service catalog" has two similar meanings. we will always refer to the latter as the "service catalog repository" to avoid confusion. This perspective requires us to think more in terms of the following: • • • Are the services that cloud consumers expect available in the catalog? Is meta data associated with virtual machine images sufficient for users to find the services they need and to distinguish among similar images? Are software license restrictions properly accounted for in the way virtual machine images are made available? Other business services are not necessarily tied to virtual machine images run in the cloud. we should think of virtual machine images as vehicles for delivering service. These commitments are usually documented in SLAs. SLAs may include requirements around: • • • • Number and type of virtual machine instances that will be available at regular times and for some length of time The duration from requesting a set of virtual servers to the time they are available Percentage of time other requirements. Service Level Management Service level management is the practice of managing commitments to cloud users. such as guaranteed number of servers. Support services. Requirements are defined in SLAs. such as ticketing systems for incident and problem management. and so on. images are maintained as part of patch and vulnerability management. but the framework is essentially the same to that which we use in non‐cloud environments. We have discussed the service catalog repository from a technology perspective with topics such as ensuring software dependencies are accommodated in images. We also use the term "service catalog" to describe a repository of virtual machine images that are available for use in the cloud.
As with availability management. This is especially true in the cloud. servers do not have identities and the software they run is a function of the virtual machine image loaded on to them by an end user. The ideal tracking system will: • • • • Function seamlessly as part of the instantiation process when virtual machines are started or when storage is allocated Collect and maintain fine‐grained detail about use. and validating in a dedicated server environment. in some cases. the new instances of the applications will have access to data. this task is easier in the cloud than in a dedicated service environment. makes it easier to execute these management operations.The Definitive Guide to Cloud Computing Dan Sullivan Availability Management Availability management is the process of ensuring compute and storage resources are available as needed to meet SLAs. one will need an efficient method for tracking use. These operations are largely self‐service steps in the cloud (whereas they are not in dedicated server environments). Cloud computing does not eliminate the need for this kind of management but does require adaptations and. In an environment with servers dedicated to particular tasks. Service management is a business practice used to control the delivery of IT services. Designing. we often use replication to keep standby servers ready to take over in case of a failure. With large numbers of users running a wide array of applications across a large number of servers. testing. the old version is easily run without the challenges of reinstalling software on a dedicated server. Usage Tracking and Accounting Services There is an old saying that if you cannot measure it. If there is a problem with the new release. The advantages stem from the fact that a new release can be deployed as another virtual machine image in the service catalog repository. 163 . Failure of a single server or even 10 servers in a cloud can be managed by instantiating the images that were running on the failed servers on other cloud servers. testing. at the user and image level Allow project or department‐level charging Feed data directly into financial reporting systems Adapting current charge back systems may require some work to allow for automated transactions indicating when instances are started or storage is allocated. Assuming data on the failed servers is persisted in cloud storage. you cannot manage it. Service Validation and Release Management Service validation and release management are procedures for testing and deploying new services to the cloud. In a cloud. One of the advantages of cloud computing is that it eases availability management. for example. and validating applications in the cloud is similar to designing.
and business units. Hybrid clouds that combine the benefits of private and public clouds can improve the efficiency. 164 . Service B. Public cloud providers can realize economies of scale that are not available to most private cloud providers. The principles are the same with cloud architectures. private clouds continue to have their benefits. and capabilities of a private cloud. Policies should be in place that define the acceptable use cases of public cloud services. this process is just a bit less challenging in a cloud environment. In the cloud. such as the ability to control the infrastructure on which private and confidential data resides. We can ask questions—such as how many physical servers will be needed to support all SLAs— rather than asking how many servers will be needed to support Department A. Of course. including the types of data that can be sent to private cloud servers and the types of applications that can be run in the private cloud. Forecasting growth with dedicated servers often requires planning for peak capacity in multiple applications. there are limits. and capacity planning are all well‐ established practices. it is imperative that security controls are in place to protect information that leaves the organization. for example. They will continue to be needed when managing a cloud but. cost effectiveness. Extending a Private Cloud with Public Services As flexible as a private cloud is. Service management practices. In cases where additional compute and storage resource are provided by public cloud providers. the costs of adding more servers or storage to a private cloud will outweigh the benefits. and so on. We manage cloud services much as we manage any service provided by IT. you might need to encrypt data as it is transmitted to public cloud servers. is a good candidate for keeping out of public cloud services. and store it in an encrypted form on cloud storage. A proprietary process or analysis procedure that instantiates significant intellectual property. but hybrid clouds must be used in a way that does not violate policies or the interests of the business.The Definitive Guide to Cloud Computing Dan Sullivan Capacity Planning Capacity planning is yet another service management process that is familiar to many IT professionals. but once again. fortunately. Businesses may find that the optimal solution is to combine private and public clouds to realize the benefits of both. you might need to set a policy that no data is written to local storage of a virtual machine running in the private cloud to prevent any possibility of a later user of that device having the ability to restore data that previously resided on the disk. usage tracking and accounting. departments. Also. we can manage to aggregate trends. with little bit less difficulty. For example. At some point.
implementing quality controls. such as service management and capacity planning. deploying applications. can be readily adapted to the cloud. and software configured for use in the cloud. Transitioning services to the cloud requires that we carefully plan other steps. including prioritizing based on business drivers. and deploying management applications. network services provisioned. it may be beneficial to consider the use of a hybrid cloud to take advantage of the economies of scale of public clouds while maintaining the control advantages of a private cloud.The Definitive Guide to Cloud Computing Dan Sullivan Summary Establishing a private cloud is a multistep process. Finally. Many existing IT processes. Hardware must be procured or re‐ assigned. 165 .
Principles of governance are not technical principles. however. but they do have implications on the technical solutions we implement. It can be thought of as a set of constraints on possible solutions to a problem. This book has followed a similar pattern for the first eight chapters by concentrating on what distinguishes cloud computing from mainframe. balancing peak load demand with average load demand. This chapter will be different. The governing policy need not explicitly mention restrictions on public clouds but that is the practical implication. This limits the use of public clouds as an extension of a private cloud. and formulating acceptable service level agreements (SLAs) with customers. still faces the typical challenges of forecasting demand for services. Throughout this book. we still have to be careful to avoid single points of failure and ensure that supporting services. 166 . we have to ensure that infrastructure is reliable enough to be available as required by SLAs. and other distributed approaches to delivering services. and to whom we may deliver them. cloud architectures are inherently distributed and therefore enable relatively straightforward failover approaches. Capacity planning is often a challenging task in IT management. The cloud services provider. client‐server. and Security There is much discussion about how cloud computing is different from earlier models of service delivery. happen fast enough and frequently enough to ensure sufficient recovery in the event of a data loss in one part of the storage system. a policy may dictate that especially sensitive private and confidential information may only be stored on devices under the complete control of the company. Growth. In addition to having enough capacity to meet the demands of SLAs. and it does—for the cloud consumer. what types of services may be delivered. Other aspects of governance influence and constrain how we deliver other services. Nonetheless. For example. per se. we have discussed how cloud computing makes capacity planning easier. such as making redundant copies of data.The Definitive Guide to Cloud Computing Dan Sullivan Chapter 9: Maintaining a Cloud Environment: Governance. Now we will focus our attention on themes common to all forms of IT and delivery: • • • The role of governance Capacity planning The need for security Governance is the guiding framework that defines how we go about implementing service delivery in the cloud. Fortunately.
In a cloud computing environment. Even with an asset management application that automatically distributes and installs software patches. 167 . and apply corrective action to each instance of the failure. Systems administrators will have to review patch reports to verify patches were applied correctly.The Definitive Guide to Cloud Computing Dan Sullivan The need for security in information management is ubiquitous. sometimes for the better. This is similar to the kind of coordination that typically occurs when servers are dedicated to particular departments or applications. For example. determine where patches have failed. vulnerable version of the image could be removed from the catalog so that it is no longer instantiated within the cloud. there is likely to be some manual intervention required. including the need to: • • • • • Maintain identity information about users Limit access to data and applications based on identity Ensure software is checked for vulnerabilities and patched as needed Prevent malicious applications from operating within the cloud Protect the privacy of confidential information The fundamental security requirements are no different in the cloud than in other models. The older. that patch will have to be pushed to each server. Cloud computing has its array of information security requirements that are similar to those found in other service deliver models. images in the service catalog can be regenerated with the patch and deployed to the service catalog. but the way we implement security controls can vary. if an operating system (OS) vendor releases a security patch and a business determines that the patch must be applied to every server. There may be instances of the vulnerable image running in the cloud in which case cloud administrators would have to coordinate with the systems administrators responsible for those instances to shut down those instances and restart with the patched versions.
1: The need to apply security patches is the same with or without a cloud.The Definitive Guide to Cloud Computing Dan Sullivan Figure 9. Cloud computing governance is a subset of corporate governance. 168 . and security in other architectures occur within the cloud. Not surprisingly. capacity planning. Businesses have boards of directors for governing the company at large. Governance Issues in the Cloud Computing Governance is about establishing a framework for directing. the same types of issues we see in governance. and security. The directions and principles established at the corporate level define the environment in which cloud computing governance occurs. capacity planning. and reporting on the implementation activities of an organization. however. monitoring. the execution can be less problematic when working with a service catalog rather than individual servers where the patch may fail for different reasons. we will consider each in turn and outline key considerations in each area. This presents a significant advantage for cloud computing administrators: We can adapt the best practices that have evolved over the past decades of IT management to cloud computing. In this chapter. The long‐term maintenance of a cloud computing environment requires attention to governance.
for areas such as finance.2: The hierarchy of corporate governance subsumes cloud computing governance. strategic planning. as required. Within service delivery. Some of the most important aspects of cloud governance include: • • • Protecting the integrity of business services Controlling access to cloud services Allocating costs for cloud services 169 . we can place cloud computing governance. Corporate governance establishes direction and management principles for the entire company with some specialization. and service delivery.The Definitive Guide to Cloud Computing Dan Sullivan Figure 9.
In another part. At the same time. can decide on the level of security they desire for communications. one part of the policy has to take precedence over the other.) Policies on confidentially should specify a combination of protections that should be in place as well as a description of the limits to those protections. Cloud consumers can make use of encrypted communications if they want. The technical aspects of these issues come into play when we start to implement the policies defined by governing bodies. In these situations. (Again. For example. we state that cloud consumers. not technical issues. policy may dictate that cloud administrators make available encrypted communications between client devices and the cloud resources. but they are primarily business issues. Cloud governance defines what is to be implemented. but they may not be required to. governance addresses what should be done not how to do it. • • • • Who will have access to the data transmitted between the cloud and outside data stores? Who will determine who will have access to data stored in cloud storage? What efforts are made to reduce the risk of inadvertent disclosure of data? Under what circumstances will normal confidentiality protections be suspended in order to prevent or investigate malicious activities in the cloud? It is the responsibility of the governing body to specify policies that answer these and similar questions that will arise. and this limits cloud consumer choices. not administrators. Protecting the Integrity of Business Services The integrity of business services entails two parts: • • Ensuring individual transactions and operations in the cloud function as expected without compromising the confidentiality of those transactions and operations Ensuring cloud services are available as expected and as agreed to in SLAs Confidentiality in the Cloud What level of confidentiality should a cloud consumer expect when using cloud resources? For example. In this example. Implementation details are delegated to others. It is not unusual for complex policies to lead to seemingly contradictory indications. 170 . cloud implementation defines how it is implemented.The Definitive Guide to Cloud Computing Dan Sullivan These areas all have implications for how we implement cloud services. protecting the cloud resources and its users is worth constraining the options of users. policy may require cloud administrators to avoid deploying software with known vulnerabilities that could compromise the security of the cloud. This may seem contradictory but it is not. In one part of a policy. This may lead cloud administrators to not offer basic ftp services and instead require a secure form of ftp. so we will not delve into the technical details of how to meet these requirements right now. the policy states that vulnerable software should not be deployed.
One department might want to negotiate an SLA that allows them to rapidly upload large volumes of data from external resources. Business units might want additional features or functionality that are not allowed in the cloud. they are constrained to the features they would like that overlap with those allowed by governance regulations. they are in place to protect the cloud infrastructure. require that any files uploaded from external resources be scanned for malware. 171 . The governing principles exist for a reason and in spite of how it might limit what business units conceive. It is conceivable that governing regulations will impose constraints on what business units might want to do. The scanning will cause the loading process to exceed the time window the customer wants.3: Governance policies define how cloud resources may be used. Internal regulations.The Definitive Guide to Cloud Computing Dan Sullivan Governance and Balancing Acts This kind of balancing act is commonly seen in law. and the business operations that depend on it. instead. however. Figure 9. data within the cloud. The freedom of speech is a well‐known right to many but that does not permit us to yell "Fire!" in a crowded theater when there is no fire.
Research and development and engineering groups may be in a second tier of users because their work is essential to the long‐term viability of the company and they have demonstrated the need for large amounts of CPU time. can be used to enforce those policies. including access to the cloud. engineering. The integrity of cloud services is protected in part by policies protecting confidentiality of data and preserving the availability of services.The Definitive Guide to Cloud Computing Dan Sullivan Availability and SLAs Another topic for governance is availability and the role of SLAs. may be given top priority under the assumption that their needs are immediate and critical. such as requiring that not more than X% of servers. the governing body may specify that SLAs will contain specifications for: • • • The number and types of servers that will be available to the cloud consumer on a regular basis The percentage of time that the agreed upon number and types of servers will be available Compensation for violations of SLAs These are SLA‐specific issues that would be negotiated between the cloud administrators and users of cloud services. A governance framework does not dictate specific rules about availability. For example. The governing body may also specify global guidelines. It is also highly dependent on security controls. will the company make the cloud available to • • • Any employee or contractor with an interest in using the resource Members of research and development. If a company invests in a private cloud. and authorization systems. 172 . but it does set guidelines. storage capacity. Some departments. or other product development efforts that require significant computational resources Employees in any department with the funds to cover the costs of the resources Once it is determined who will have access to the cloud. Within the group of users eligible to use cloud resources. there may be a further division by priority. security controls. such as identity management. A third tier may be everyone else in the company who will have access to resources not consumed by the other two groups. This type of global constraint further defines the boundaries of actions that cloud administrators can take. authentication. Controlling Access to Cloud Services One of the most fundamental considerations in the governance of cloud resources is determining who has access to those resources. or other resource be down for routine maintenance at the same time. such as finance.
Let's also assume the server was purchased for $5000. the actual prices cloud consumers pay be me a mix of both approaches. Pricing Cloud Services There are two broad approaches to determining the costs for cloud services: cost allocation and competitive pricing. A better approach is to use an average cost and an average utilization rate for each server.24 per hour. Also. (For simplicity. In practice. and incurs $300 in power. and other miscellaneous charges for a total of $6300 in costs over 3 years. In practice. there may be limitations on the resources they can acquire. we have to hope we have made good estimates. cooling. When we set prices. we'll assume that this server only runs open source software so that there are no software licensing costs). Trying to assign each server its own individual total cost of ownership (TCO) would generate more accounting work than it is worth. For example. 7 days week for 3 years for a total of 26. Let's assume a basic server can run four virtual servers. The server runs 24 hours a day. The same model may work well within a business where IT units are treated as cost recovery centers and not profit earning centers. the cost of a service is equal to the cost of purchasing and maintaining equipment and providing labor to support the service divided by the units of the service provided. This kind of cost allocation model is found in government institutions where pricing is driven by the need to recover costs rather than to earn a profit.The Definitive Guide to Cloud Computing Dan Sullivan Within each group. servers in the cloud may have been acquired at different times for different prices. so there will be time when some servers are not utilized and therefore not charged to any customer. Regardless of who can access cloud services. For example. An example can help clarify some of the details. the assumption that a single server will run 24×7 for 3 years straight is unrealistic.280 hours divided by $6300 or $0. Finally. The hourly cost of providing this server is 26. this simple cost allocation model will need some modification. clouds are designed to accommodate varying peak demand periods. we have to make some assumptions about utilization rates and availability of servers. rack space. requires $1000 in labor to maintain over the course of 3 years. so they may run their virtual server instances for as long as they like but are limited in the number of virtual servers they can instantiate at any one time. but we will discuss them separately and then see how they can be merged. Engineering may need to run large calculations for extended periods of time. 173 . At its most basic level. If we are overly optimistic about utilization and availability. In the cost allocation model. someone has to pay for them.280 hours. we may find that in fact we do not recover all the expenses we had planned for and are left with a revenue or cost recovery shortfall. the top‐tier Finance group may have access to as many servers as they like but can run them continuously for only 48 hours if other jobs are waiting to run in the cloud. Cost Allocation Cost allocation is a pricing model that is driven by the costs incurred by the provider of the service.
Planning for Growth One of the key benefits of using cloud computing is that users of the cloud can rapidly scale their resource use up and down. Another facet of long‐ term maintenance is capacity planning. and service development into the cost of providing services. Such high‐level constraints are insufficient guidance for providing a governing framework for a private cloud. Users no longer need to worry about maintaining peak capacity infrastructure—it is available in the cloud when it is needed. limiting access to cloud services. which is common in business. This certainly makes sense for a public cloud. in some cases. but does this pricing model have a place with private clouds used only by internal customers? Yes. (This is similar to profits or retained earnings. but those have specific accounting definitions. It is up to the governing body to determine which approach better serves the long‐term goals of the enterprise. is competitive pricing or pricing according to what the market will bear. By charging more than the actual costs. Further regulations around protecting the integrity of services. so can the storage utilized. and allocating the costs of the cloud are all required. so we will try to avoid using those terms. such covering the costs associated with replacing failed devices that may or may not be under warranty To fund experimental cloud services that are provided for free in return for feedback on the services The cost recovery model does not provide a mechanism for this kind of retained reserves funding. but that is a bit counter to the intention of the cost recovery approach. One could imagine incorporating the cost of future expansion. Cloud computing governance is a subset of corporate governance. the number of servers dedicated to the task can increase. Neither cost recovery nor competitive pricing is inherently better or worse than the other.) This reserve can be used in several ways: • • • As a resource for funding future expansion of cloud infrastructure To mitigate the risk of unanticipated problems. As workloads increase. risk management. it centralizes the burden on the cloud provider. As data volumes grow. Presumably public clouds use a competitive pricing model where their price for a unit of service includes the costs we described earlier plus an additional amount for profit. 174 . Regulations put in place at the enterprise level constrain what can be done with cloud services. a cloud provider can generate a reserve of earnings that are not allocated to cover the costs of providing the cloud services. Cloud computing does not eliminate the need for capacity planning.The Definitive Guide to Cloud Computing Dan Sullivan Competitive Pricing Another approach to pricing.
Then we turn our attention to understanding how demands for capacity of various resources are expected to grow.4: With the adoption of cloud computing. Centralized cloud providers will have to address capacity planning issues common throughout IT: • • • • Researching customer expectations for current and future resources Estimating costs of future services Planning how to deliver needed capacity in the most efficient manner Identifying dependencies that can influence how new capacity is added Capacity planning begins by identifying key resources that affect the ability of service providers to meet SLAs.The Definitive Guide to Cloud Computing Dan Sullivan Figure 9. the scope of capacity planning shifts from individual applications and departments to a centralized cloud service provider. Key Resources in Cloud Computing The key resources in cloud computing are those that limit the ability to deliver services: • • • Physical servers Storage Network bandwidth 175 .
and cooling. a shortage in the other will inhibit the ability to deliver services. storage. Servers. How are we to accurately predict the future needs of cloud users? Especially when their workloads and peak demands can vary so much? The answer is SLAs. SLAs probably will not explicitly state requirements related to environment. Similarly. such as a single quad‐ core processor with 16GB RAM Total amount of storage available Network throughput Average server utilization Number of virtual machine instances available in the service catalog Percentage of time SLAs are met 176 . Baseline Measures We can think of a baseline measure as the average load on the cloud for computing. With these key components and details of SLAs. if network bandwidth is saturated. If there are ample servers and sufficient network capacity but we run out of storage. storage devices.The Definitive Guide to Cloud Computing Dan Sullivan Each is a limiting factor because in spite of adequate capacity in two of these. One of the advantages of starting with SLAs and historical data is that it is reasonably reliable and accurate data. and how much heat generated by equipment can be adequately cooled or vented. and network equipment require space. storage. storage‐dependent workflows will be blocked. how much power can be reliably and consistently delivered. and network services at some point in time. There are limits to how many racks can fit in a data center. Cloud consumers are responsible for estimating their current and future requirements in terms of computing. The purpose of taking a baseline is to understand what level of service can be delivered by a particular amount of cloud infrastructure. we can begin to formulate baseline and future growth projections. and possibly longer if customers use long‐term contracts to lock in favorable pricing. A baseline measure of cloud service delivery might include: • • • • • • Number of servers with all servers normalized to a standard. the ability to move data into and out of the cloud is constrained. Another factor that is easy to overlook is the physical environment in which the cloud infrastructure resides. Assuming historical data is collected properly. storage. Baseline and Initial Growth Projections SLAs and historical data provide a starting point for establishing baselines for the amount of resources required to meet service delivery needs. These contracts between cloud providers and cloud consumers specify what levels of resources are expected by cloud consumers and what the cloud provider commits to. we have a detailed record of what happened in the past. and network demands. and network services. Cloud providers are responsible for ensuring that the cloud can meet the aggregate demand for resources specified in SLAs. SLAs provide guidance on what will occur in the near future. power. instead they have to be derived from the details about servers.
5 shows. It is worth noting that increasing utilization and throughput can happen in a fairly incremental manner while the addition of infrastructure tends to happen in a more step‐wise manner. They measure. Average utilization is important because it influences the total throughput of the cloud. For example.5: Capacity is often acquired in bulk. we can plan for growth projections.The Definitive Guide to Cloud Computing Dan Sullivan The first three metrics capture the basic capacity of the cloud. in some ways. the implementations should be run on the same hardware under the same network load running the same OS and application stack. If utilization is low. although there may be spikes or temporary drops in utilization. Figure 9. or we could maintain the same level of infrastructure and increase the utilization to 80%. these metrics are not adequate for comparing the performance of different implementations of the same algorithm. Utilization tends to grow incrementally. For that. as Figure 9. we double the number of servers and other infrastructure while maintaining a 40% utilization rate. to double the throughput of a cloud with 40% utilization. These metrics are not precise enough for all performance‐related tasks. the overall throughput of the cloud infrastructure. 177 . One way to improve the throughput of a cloud is to increase utilization. Growth Projections After establishing baseline measures. The purpose of collecting these measures is to be able to compare cloud infrastructure capacities in order to estimate what is required to meet a set of SLAs. giving a stepwise growth in capacity. There are two types of growth we need to account for: growth in capacity and growth in usage or throughput. For example. there will be excess capacity that is not utilized.
and if revenue projections are on target. and so on is so low that it often makes sense to perform these operations in bulk. the marginal cost of installing a second. a company could follow a steady incremental growth plan. The funds are not available any sooner.The Definitive Guide to Cloud Computing Dan Sullivan Growth in Utilization Utilization grows at a rate determined by a number of factors. this might make sense. The IT manager will likely purchase the equipment in three periods as the funds become available. fourth. another option has become available for providers of private clouds: expanding by using public cloud compute and storage resources. there may be sharp and sudden rises in the number of transactions (think of the Apple iPad launch). Some of these growth factors are likely to lead to incremental growth. so there is no way to accelerate the purchases. It makes no sense to leave equipment in the shipping containers. a stepwise growth in capacity makes more sense. Another factor that leads to the stepwise growth in capacity is the economics of hardware installation. A merger or acquisition can add a large pool of potential cloud service customers to a company and drive demand for services sharply higher. such as an increase in the • • • Volume of work performed by existing cloud consumers executing existing workflows Number of distinct workflows executed by existing cloud consumers Number of cloud consumers For each of these types of increase. An IT manager creates an infrastructure budget based on projected demand. In many cases. Sudden and dramatic growth in demand can arise from changes in the organization. and other factors and determines that 25% of the budget will be available in the first quarter. Conceivably. unless demand is low. there can be corresponding decreases. there can be a progressive growth in the volume of transactions that need to be processed. If the company is a rapidly growing Web infrastructure provider. borrowing costs. cash flow projections. Growth in Capacity Although demand for cloud services can change in fairly incremental ways. The hardware will be brought online as soon as possible. 50% in the third quarter. another 25% in the fourth quarter. in which case the purchases were unnecessary. The CFO takes into account revenue growth. For example. In some cases. For example. If one goes to the trouble to install a single rack in a data center. 178 . divesting in a line of business can cause sudden drops in demand and therefore overall utilization. capacity changes tend to be more bulk. As a line of business expands into new markets or launches new product lines. As the practice of cloud computing has matured. Consider a typical budget cycle. a company could add 100 high‐end servers to the cloud every week for the foreseeable future. a department may re‐engineer its processes and stop using an application that had run in the cloud. This reality is driven by economics. Similarly. stepwise changes. third.
Public clouds may be able to offer lower prices because they benefit from economies of scale that are not available to private cloud providers. 179 . Elastic Scaling and Hybrid Clouds: The Benefits Combining resources with a public cloud allows private clouds to rapidly expand capacity without the capital investment of expanding a private cloud. As is often the case in IT. Also. has several advantages as well as some disadvantages. resources in a public cloud can be commissioned and decommissioned faster than adding or removing comparable physical resources in a private cloud. Private clouds are designed according to the particular needs of a single business and governed by policies needed to protect that business. Private cloud administrators hide the implementation details from end users. The two are designed for different purposes and serve different needs. Public clouds are generic computing and storage resources with policies designed to accommodate a wide range of users. and control over the service catalog than a private cloud does. known as a hybrid cloud. choosing between the two is a matter of choosing a solution that best fits a particular set of requirements. The cost of a private cloud may be less than that of a public cloud.The Definitive Guide to Cloud Computing Dan Sullivan Expanding Using a Public Cloud The reasons that a private cloud provider would want to make use of a public cloud parallel the reasons that end users are drawn to public clouds: elasticity and cost effectiveness. The combination of private and public clouds. Also. public clouds may have less in the way of security. Figure 9.6: Hybrid clouds appear to users to be functionally equivalent to private clouds. This is not criticism of private clouds. auditing.
maintain redundant copies of the service catalog in different data centers. For example. the jobs running on those servers can be restarted on other servers. Mitigating Risks Through Architecture Capacity planning should take into account the need for excess capacity in case of failures in some parts of critical infrastructure. Catastrophic failures require advance planning. the volumes of data to transfer are low. running data back and forth between data centers on portable disks). Hybrid clouds are a viable option in many cases when expanding a private cloud is not a practical option. and ensure that policies and procedures are defined and implemented in the same way across data centers.5). earthquake. When the public cloud can be used to run applications that do not instantiate protected intellectual property. the excess capacity in the cloud may not be enough to accommodate for the loss. When a small number of servers fail. Two factors should be considered when planning such excess capacity: the physical distribution of data centers and the need for redundant infrastructure. In addition to building data centers in different areas. if an entire data center becomes inaccessible or a large number of servers is down because power distribution is disrupted to a large number of racks within a data center. In such cases. Public clouds can supplement private cloud capacity for conventional workloads. Physical Distribution of Data Centers Data centers in different geographical locations reduce the risk that two or more data centers will be struck by the same catastrophic event (for example. we need to plan to maintain additional capacity.The Definitive Guide to Cloud Computing Dan Sullivan Elastic Scaling and Hybrid Clouds: The Disadvantages The primary disadvantage of a hybrid cloud is that some data is moved outside the corporate firewall. 180 . This situation can often be accommodated by the excess capacity that can exist because of the difference in the capacity deployed and the capacity required to meet utilization requirements (see Figure 9. public cloud providers offer customers the option of shipping disks to a data center for bulk loading rather than copying data over the Internet. and the security requirements are minimal. public clouds can also contribute to mitigating the risk of hardware failures. and flood). Public cloud providers can make significant efforts to protect their customers' data (they certainly have no incentive to risk a data breach of one of their customers) but that may not be enough for security‐conscious executives and managers. regional power loss. Moving large volumes of data can also be a hindrance. then public cloud services make sense. In a cloud computing version of the old "sneaker net" (that is. we need to keep replicas of data in different data centers.
They will also require comparable backup power systems. The third and final topic we will consider with regard to long‐term maintenance of a cloud is the need for security. 181 . It also provides for more efficient deployment of redundant infrastructure. which can mitigate the risk of failures in the cloud. storage. Redundant Infrastructure Data centers will of course need servers. it might be difficult to realize a highly redundant. Capacity planning has traditionally been challenging in IT. Centralizing the management of infrastructure within the cloud allows for pooled utilization and capacity. and network infrastructure.7: Routine failures are readily accommodated in clouds but catastrophic failures require failover planning and additional infrastructure. and backup cooling and venting systems to reduce the risk of a single point of failure in the infrastructure. multiple Internet service providers (ISPs).The Definitive Guide to Cloud Computing Dan Sullivan Figure 9. When working within the constraints of department or line of business budgets. rapid failover architecture without significant cost.
such as those for research and development and engineering purposes. The looser the purpose (for example. as is so often the case. according to what criteria? How should identities be removed to ensure the least risk of failing to remove someone's identity that should be removed? What type of monitoring on the activity of identities is required? How frequently should identities be audited? The concern here is with long‐term management and maintenance. A primary concern in the cloud is how to maintain an accurate and up‐to‐date database of identities. Common questions that arise with identities in the cloud are: • • • • Who should be added as a user in the cloud? All employees? Full‐time employees only? Should contractors be added.The Definitive Guide to Cloud Computing Dan Sullivan Security in the Cloud Key considerations for long‐term planning for security in the cloud are similar to those for other aspects of enterprise security: • • • • Identity management Entitlements and access controls Vulnerability assessments Patching and image management These are not fundamentally different from what needs to be done in other IT environments but. It may not be sufficient for employees changing roles and losing privileges to the cloud. They are just outside the scope of this discussion. Identity Management in the Cloud Identity management is the practice of maintaining information about users of IT resources and services. Ideally. More restricted clouds. Removing identities is also an issue. to provide general computing and storage services to all business units for all purposes). This may not account for contractors and consultants who are granted access to resources. we have to have a clear understanding of the purpose of the cloud. will have correspondingly restricted groups of users. different implementations of similar services and functionality bring with them varying dependencies and maintenance requirements. Before we can address whose identities should be added to the cloud. although they are certainly important. so implementation issues are not considered. changes to a centralized HR system would trigger the removal of identities in the cloud when an employee leaves the company. and if so. 182 . the more broadly defined is the set of potential users.
so it is reasonable to expect software vendors will quickly adapt their pricing models to the cloud. or entitlements as they are sometimes called. 183 . These often are based on four categories: public data. software developers create better ways of performing the same task and release new versions of applications with better performance. Applications should be controlled along similar lines as data. and should be restricted to individuals who have a legitimate need for the application. no one would ever be granted entitlements to data or applications that are not required for them to do their jobs. Vulnerability Assessment and Patching It is widely assumed that complex software has flaws. if one or two individuals are using cloud resources at rates significantly higher than others in the same role. For example.The Definitive Guide to Cloud Computing Dan Sullivan Routine monitoring of activities associated with identities can help detect anomalous events. These privileges. private data is about a customer or other person and is not to be shared outside a restricted group. Policies and procedures should be in place in the cloud to protect a number of entitlement related issues: • Granting access to data according to a data classification scheme. Entitlements and Access Controls Entitlements should be associated with well‐defined roles in a business. Software licensing models tend to evolve along with server technology. sensitive data. In all of these cases. we will turn our attention to ensuring those applications are functioning as expected. designers create applications that although coded according to specification. Some applications contain proprietary knowledge. private data. Employees change roles. financial analysts should have access to historical financial transactions and various data marts and business intelligence applications. At other times. Next. and confidential data. Public data can be shared without harm. Identities provide a means to associate privileges with users. such as a risk scoring program. Sometimes bugs are the result of programmers making mistakes in their coding. however. For example. also require oversight. controls on data change. Other times. it may be an indication of unauthorized use. and sales forecasts may be restricted to a small group of executives. Under ideal conditions. marketing strategies. Software licensing may restrict the number of users that can simultaneously run an application or restrict an application's use to a set of named users. there are reasons to update the software with vendor‐provided patches. sensitive data should not be shared broadly but would not cause serious harm if it did. access to product designs. Less frequent but routine auditing of the identity management database can help detect cases where identities that should have been removed or disabled remain active. • • Entitlements and access controls protect how data and applications are used. and new applications are brought online sometimes with overly broad execution privileges. function in unanticipated ways. and confidential data is company‐related data that would cause significant harm if disclosed.
The Definitive Guide to Cloud Computing
Dan Sullivan
Patching is a common practice and can significantly improve the security and quality of the software we run. It is not without risk, though. A patch may correct one flaw while introducing another. A patch could render an application that worked well in one configuration non‐functional. Policies should be defined for the cloud service catalog that specify when and how patches should be applied to virtual machine images in the cloud. These policies should consider: • What would trigger the decision to apply a patch? Reasons include a regular patch release from a vendor, a notice in the trade press about a newly discovered vulnerability in a popular software application, or through the use of vulnerability scanning software with the company. What testing should be done prior to releasing a patched image? In some cases, it may be sufficient to release a new version while maintaining the older version in the service catalog. Users would then be free to choose which to run. This may work for non‐security patches, but images with known, high‐impact vulnerabilities should not be left for general use.
As with other security aspects, patching and vulnerability management practices outside the cloud can be readily adapted to the cloud.
Long‐term management and maintenance of a cloud environment requires attention to governance, capacity planning, and security issues. Governance issues include framing policies for the cloud that fit with overall corporate governance, defining the scope and structure of SLAs, and formulating a cost recovery mechanism for cloud services. Capacity planning is based on SLAs and strategic direction of the company. SLAs provide a baseline for determining the capacity needed to meet SLAs while maintaining reasonable utilization rates with some tolerance for the inevitable hardware failure. Long‐term security concerns include the need to address identity management, entitlements, vulnerability assessment, and patching. These are not new management considerations for IT professionals and many best practices that have been created over the past decades can continue to serve us well if we adapt them to the particular requirements of a cloud environment.
The Definitive Guide to Cloud Computing
Dan Sullivan
Chapter 10: Key Steps in Establishing Enterprise Cloud Computing Services
Adopting cloud computing technology in an enterprise can produce substantial improvements in service delivery and cost control. That is, if it is done right. The driving force behind the use of any technology should be a business imperative. For that reason, the first key step in establishing enterprise cloud services is to understand the business objectives that can be served by the technology. In this, the final chapter of The Definitive Guide to Cloud Computing, we begin by examining how to align business drivers with cloud services. This process includes understanding business objectives, identifying weaknesses in existing IT service delivery, and prioritizing the multiple objectives that can be served by cloud computing. Once we have established what we want to achieve with cloud computing in the enterprise, we move on to the second key step in the process: planning. The planning phase requires a combination of business and technical knowledge that typically requires a team of professionals from across the organization. Some of the issues we must address at this stage are assessing the current state of readiness, determining the best cloud model for a given set of requirements, and planning for long‐term management and sustainability. The implementation phase follows the planning stage. The details of this phase will vary depending on whether a business decides to adopt a private cloud model, a public cloud service model, or a hybrid setup. Later in the chapter, we will examine issues that should be considered in each case, such as reallocating server hardware when implementing a private cloud or establishing service level agreements (SLAs) with a cloud provider when a public cloud service is used. The fourth key step in establishing cloud computing services is to develop a maintenance model. Maintenance has both technical and business dimensions. Technical issues include establishing procedures to monitor services, identifying and correcting failed services, and maintaining proper patch levels of software underlying cloud services. The business side of maintenance focuses on tasks such as establishing value metrics and planning for adequate capacity.
The Definitive Guide to Cloud Computing
Dan Sullivan
As Figure 10.1 depicts, implementing cloud computing in the enterprise will introduce can ongoing life cycle that mirrors many of the steps we follow to establish cloud computing services. For example, business drivers will change over time. New services will be rolled out. Strategic initiatives will be launched. Service offerings will be curtailed as the business shifts its focus to new opportunities. The process of aligning cloud computing services with business drivers is not a one‐time operation. Cloud computing services may be regularly adjusted to meet incrementally changing requirements, but the services should also undergo periodic comprehensive review to ensure that the provided policies and procedures in place continue to meet the long‐term objectives of the organization.
Figure 10.1: The key steps to transitioning to cloud services will persist in a similar form in an ongoing life cycle. Just as aligning business objectives and technology is part of the cloud computing life cycle, so are the other stages outlined here. Planning logically follows from strategic assessments, implementations follow planning, and maintenance follows implementation. Getting the cloud computing life cycle started in the right way will help establish the framework for the ongoing job of adjusting and adapting cloud services to the dynamic needs of the enterprise.
The Definitive Guide to Cloud Computing
Dan Sullivan
Aligning Business Drivers with Cloud Services
Throughout this book, we have discussed the characteristics of cloud computing, delved into some of the technical details, and discussed the advantages and disadvantages of various models of cloud computing. These are obviously important considerations, but they are not the only ones. In fact, the most fundamental question we can ask with regards to cloud computing is "Why?" Cloud computing, or any technology, is not an end in itself. Technology is deployed to serve a business purpose. To reduce the risk of misusing or misapply cloud computing in an organization, we are well served by undertaking three tasks early in the cloud computing adoption process: • • • Understanding business objectives Identifying weaknesses in existing IT service delivery Prioritizing initiatives
Together these three tasks help to keep the focus, and therefore the benefits, of cloud computing on business needs in a way that maximizes the return on investment.
Figure 10.2: Aligning business objectives with cloud computing deployments is a threestep process.
Understanding Business Objectives
At the most coarse level, business objectives can be categorized into two types: developing new products, services, and capabilities and improving existing processes. New services that are especially well positioned to take advantage of cloud computing services are those that are compute‐ or storage‐intensive. Cloud computing can enable innovation not practical under other IT models. For example, consider a manufacturing firm that produces customized machine parts.
The combination of innovative software and cloud computing resources allows the engineers to off‐load automatable design tasks. When you are examining business objectives and assessing the opportunities for offering new services. The manufacturer also does not have the IT expertise to implement and maintain a high‐performance computing environment with clusters of high‐end servers. Using public cloud services.The Definitive Guide to Cloud Computing Dan Sullivan Cloud Computing Enables Innovation Customers continue to use the manufacturer because of the company's high‐quality parts even though the time required to define the requirements for new parts is longer than most customers want. the manufacturer could run the compute‐intensive CAD software in the cloud as needed. Engineers could be more productive if they could better leverage the capabilities of computer aided design (CAD) software. The manufacturer is well aware of its customers' time constraints but it has decided not to sacrifice quality for speed. The fundamental problem is that highly‐ skilled engineers are required to do the design work and the manufacturer cannot carry too many of these professionals. • • • Is your ability to deliver the service limited by available computing or storage resources? Can some parts of labor‐intensive processes be automated? Can a workflow be changed to automate 80% of the workload while leaving the other 20% for employees? Existing workflows may not obviously lend themselves to cloud computing but re‐ engineered forms of the same workflow may be more amenable to automation. 188 . consider several factors about workflows that make them candidates for cloud computing services. freeing engineers to work on additional design problems. but the kinds of analysis they need are compute‐ intensive.
189 .3: Cloud computing can enable increase productivity through the innovative treatment of existing applications.The Definitive Guide to Cloud Computing Dan Sullivan Figure 10.
especially during downturns in the business cycle. The potential to apply innovative application of existing services and to experiment and quickly implement new services are two of the key types of business opportunities that should be considered when trying to understand how to leverage cloud computing and align it with business objectives. such as servers and storage arrays.6). This can take on several forms: • • • • Inefficient business processes and workflows Below‐expected productivity from professional staff Poor utilization of IT resources Prolonged time to complete IT processes. Well‐run businesses will work to get a reasonable return on that investment. Not a single server needs to be purchased. Improving Existing Processes Another key type of business objective is cost control. There may be uncertainty about the rate of growth. IT resources. Demand may be low at first but expected to grow. especially when they are dedicated to a single business process. Pilot projects can be readily started using only cloud resources. With no significant capital investment required to start such a project. On‐demand computing and storage can help in just this type of situation.4 (which first appeared in Chapter 1 as Figure 1. 190 . This type of uncertainty may be enough to derail an otherwise promising plan. such as deploying hardware or patching software Inefficient business processes and insufficient productivity of professional staff can be addressed using the methods described earlier in the discussion on innovation. however. If a pilot project is successful. are costly investments. The other cost control areas require further elaboration. Eliminating the procurement process saves not only money but also time. can get in the way. Spikes in demand or temporary (or even prolonged) downturns in demand are readily accommodated by adjusting the level of cloud resources allocated to the service. shown in Figure 10. Technical issues. there is greater freedom to experiment with new business services. the service can be rolled out to larger groups of customers and cloud resources can be scaled accordingly. Chapter 1 analyzed this problem and showed how cloud computing more efficiently allocates computing resources. One of the most significant problems is low utilization of servers.The Definitive Guide to Cloud Computing Dan Sullivan Accommodating Varying Demand for Services Another factor that may hold back a business initiative is uncertainty about demand.
The most important of these features are: • • • • Virtualized servers Standardized catalog of software and services Self‐service allocation and management Cloud management applications for IT administrators 191 .4: Cloud computing more efficiently utilizes computing resources than dedicating servers to single operations that have widely varying levels of demand. The combination of a number of features of the cloud delivery model often makes it a cost‐effective approach.The Definitive Guide to Cloud Computing Dan Sullivan Figure 10. Also consider the cost of IT support staff when evaluating business drivers behind a move to cloud computing.
Any one of these areas can represent a weakness in the ability to deliver IT services. Consider an example: A line of business wants to deploy a new service that will require several servers and a commonly used application stack. When new hardware is procured. and other infrastructure to support the new servers If this same new application were deployed in the cloud. 192 . Application administrators would start virtual servers running the necessary applications on an as‐needed basis. The list could go on to include policies and procedures that describe how to implement security controls.The Definitive Guide to Cloud Computing Dan Sullivan This combination of features allows fewer IT professionals to support a larger number of users and more hardware resources than would be possible under dedicated server/dedicated systems administrator approaches. By identifying steps in IT processes that hinder other business operations. there are procedures to follow. Identifying Weaknesses in Existing IT Service Delivery IT departments have policies and procedures for delivery services. so questions about infrastructure would not arise. software maintenance. there is a procedure to follow. and systems monitoring and auditing. Implementation issues such as these put a drag on innovation or improvement to existing processes. A license management scheme (for example. we would still have to address these same issues. but we could do it more efficiently. Everything the department wants is well within the ability of the IT department to support but still there are problems: • • • • The time required to review the server orders and verify the configurations are correct Determination of whether additional licenses are required to run the application stack Identification of IT staff to perform the installation and systems administration tasks Determination of where the hardware will be located and assurance that there is sufficient power. Hardware would be in place. When new applications are brought online. Servers would not have to be ordered just for this application. network management. site licenses) would presumably already be in place for cloud‐based applications. network connections. we can better understand where we can apply cloud computing to avoid those issues. The installation process would be reduced to ensuring the correct images are available in the service catalog.
The Definitive Guide to Cloud Computing Dan Sullivan Prioritizing Initiatives Chapter 4 outlined common high‐priority objectives that are worth repeating: • • • • • • Controlling costs Expanding market share in mature industries Expanding into new markets in growth industries Improving customer service Improving customer retention Increasing cross selling The last step in understanding business drivers for adopting cloud computing is prioritizing all the ways we improve business operations. Each of these implies either a direct cost. Planning for Transition to Cloud Computing The planning phase of the cloud transition is primarily focused on technical issues: • • • • Assessing the current state of readiness Indentifying the differences between current infrastructure and the infrastructure to deploy for the cloud Determining the best cloud model for your requirements Planning for long‐term management and stability Not surprisingly. improving IT service delivery. a business will be in a firm position to take on the challenging task of planning for a transition to cloud computing. and prioritizing among all the potential ways to leverage cloud computing. identifying weaknesses in existing processes. such as labor costs. By understanding business drivers. or opportunity costs. reducing the barriers to introducing new services. We can prioritized based on the value of supporting innovation. the first step in getting to where we want to go is to understand where we are. and reducing the staff required to maintain a particular level of service delivery. Aligning business initiatives with cloud computing services is the essential first step in adopting cloud computing. such as those associated with delays in releasing new products and services. 193 .
The Definitive Guide to Cloud Computing
Dan Sullivan
Assessing the Current State of Readiness
Cloud computing takes advantage of a particular style of application architecture. The closer we are to that style when we begin, the better off we are. Three elements of this style are Web application architecture, self‐management of compute and storage services, and standard platforms and application stacks. These elements were described in detail in Chapter 7, so they will be only briefly described here. Web application architecture is decentralized and depends on multiple processes running on multiple servers. A simple three‐tiered model includes a server for persistent storage, which is usually a relational database; a middle tier of an application server, such as a Java J2EE application server or a .NET application; and a client tier providing a user interface (UI). A common variation on this model is to have several application servers providing services to a Web server that coordinates those services for a client interface (see Figure 10.5).
Figure 10.5: A common decentralized amenable to cloud computing model uses a multitier stack to implement applications. The more centralized an application, the more difficult it is to take advantage of the cloud. For example, in the application architecture shown in Figure 10.5, if any of the application servers reaches capacity, another instance of that application server could be instantiated to assist with the load. Centralized applications do not offer the opportunity to scale parts of the application like that.
The Definitive Guide to Cloud Computing
Dan Sullivan
One of the cost control benefits of cloud computing is the ability to offer self‐service management to cloud consumers. This setup removes high‐cost IT professionals from common tasks such as starting instances of virtual machines or allocating storage for an application. The software required to implement self‐service can be deployed in the next phase of the transition process, but cloud consumers should be in a position to take advantage of self‐service features when they arrive. Another factor to consider is how standardized your application stacks are. Are departments running a wide range of applications and different platforms? Do you support three or four major relational databases? Are departments running different versions of Windows and Linux operating systems (OSs)? The answers to these questions will give you some indication of how standardized your organization is with respect to application stacks. The transition to cloud computing can be an opportunity to prune the set of supported applications. This will further improve the cost benefits of cloud computing by reducing the demand for patching, licensing management, and support services related to different applications.
Indentifying the Differences Between Current Infrastructure and the Infrastructure to Deploy for the Cloud
Cloud services can run on commodity hardware. They can also run on specialized hardware assuming virtualization services are available. What set of hardware servers, storage, and network equipment is available in your organization? The optimal set of infrastructure components is a function of several factors. On the one hand, if hardware is in place, it seems logical to use it; on the other hand, the greater the diversity in equipment, the greater the administration and overhead costs. Some things to consider with regard to assessing what you have and what you would like for hardware infrastructure include: • • • • The capacity of servers to support multiple virtual instances, including processor speed and memory capacity The ability of servers to run software in the services catalog The range of support skills required to maintain the infrastructure Power consumption and cooling requirements
The goal is to provide needed cloud services at the lowest cost. This requires us to consider the full range of expenses, from the cost of new hardware to the cost of maintaining power and cooling for older hardware that may require more support than newer hardware. The best combination of new and existing infrastructure is a function of your resources, environment, and requirements. There is no single answer or simple formula for determining the optimal solution.
The Definitive Guide to Cloud Computing
Dan Sullivan
Determining the Best Cloud Model for Your Requirements
As we have described throughout this guide, there are three models for delivering cloud services: private, public, and hybrid. Which is the best option for you? A private cloud is suitable for enterprises that have the infrastructure, support skills, and management framework to maintain such an architecture. We use the term infrastructure broadly, to include not only IT hardware but physical infrastructure such as data centers, redundant power supplies, and multiple high‐speed Internet connections. IT professionals running a private cloud will be required to manage large numbers of similarly configured servers, multiple disk arrays, a complex array of network management systems, and robust security controls. A management system must be in place as well to implement cost recovery, capacity planning, service delivery, licensing negotiations, and other administrative capabilities. These are significant barriers to adopting a private cloud model, but there are advantages as well. Your organization has complete control over the service catalog, who is allowed to use cloud resources, and the ability to monitor all cloud services. The fact that data and applications would not have to reside outside the corporate firewalls can be a substantial advantage from a compliance perspective. A public cloud has several advantages: • • • • Minimal capital expenditures Ability to maintain existing infrastructure in its current configuration, allowing for a period of time in which both existing and new cloud‐based instances are used Possibly lower costs per unit of computing service or storage because of the economies of scale Less management overhead for day‐to‐day operations but potentially more overhead for negotiating, monitoring, and enforcing SLAs
The potential drawbacks of a private cloud include the need to move sensitive data outside the corporate infrastructure, the potential costs of transmitting large volumes of data over the network, and the delays in moving data into the cloud by shipping storage devices (done in some cases to reduce upload costs). A hybrid cloud can offer the advantages of both the private and public cloud. Sensitive information can be maintained in a private cloud while other data is moved to the public cloud. Existing infrastructure can be readily redeployed to a cloud while older or less amenable hardware is not. Initial capital expenditures may be reduced because peak loads in the private cloud can be accommodated by allocating resources in a public cloud. Once again, there is no solution that is optimal for all cases. The advantages and disadvantages of each model must be weighed against the business requirements and constraints.
The Definitive Guide to Cloud Computing
Dan Sullivan
Figure 10.6: A combination of private and public clouds can enable an organization to realize the benefits of both.
Planning for Long‐Term Management and Stability
Implementing a computing and storage cloud is a long‐term proposition that requires attention to a number of areas in addition to those already mentioned. In particular, we need to plan for security, disaster recovery, and maintenance of physical infrastructure. Security considerations include protecting physical infrastructure as well as logical access to services and resources. Cloud data centers will require the same types of physical protections as one would find in any large data center. Access to infrastructure should be limited to those with legitimate needs. The site should be monitored and security procedures audited. Fire suppression equipment should be in place. Logical access controls begin with identity management. Policies should be in place defining who has access to various cloud resources, such as servers and applications. Licensing restrictions should be taken into consideration as well. Policies and procedures should define how authentication and authorizations are granted, monitored, and revoked. Long‐term management includes planning for disaster. Maintaining multiple data centers may be a reasonable strategy for some private cloud users but not others. The costs can be prohibitive. One alternative is to use a public cloud for disaster recovery purposes, although there are still issues regarding confidentiality and compliance.
Cloud computing.7. implementation. Implementing a Cloud Infrastructure Analyzing business drivers can be challenging because of complex. Implementing a Private Cloud The key tasks to implementing a private cloud center on deploying hardware and establishing operations. Equipment will fail. The next stage of the process. The specific challenges will vary depending on the type of cloud model that is being used: private. Planning can be difficult because one has to merge both business requirements and technical constraints in a way that serves business objectives. With large numbers of servers and disks. it is reasonable to expect regular equipment failures. New equipment and applications will be added while others are retired. will fail as well. When new hardware is used for cloud deployments. Services. like the business environment it serves. as depicted in Figure 10. Backup power supplies and redundant Internet providers should be used. 198 . interdependent goals and objectives. the transition is relatively straightforward. New business requirements will emerge. or hybrid. Power will go down. public. Even with long mean times between failures. is difficult primarily for technical reasons. Three such tasks are: • • • Reallocating and deploying servers Establishing software and application management procedures Implementing a management framework Reallocating servers must be done carefully to avoid disrupting existing business services. is dynamic. parts will fail. Applications can continue to run on legacy hardware as long as needed as those same applications are moved to the cloud.The Definitive Guide to Cloud Computing Dan Sullivan Maintaining the physical infrastructure of a cloud is an ongoing operation. when we are dealing with thousands of pieces of equipment. such as power and Internet access. A useful rule of thumb for managing cloud computing and the services it can provide is to assume that change and innovation are inherent.
A basic challenge is to keep services available while migrating hardware from an application‐ centric use of servers to a cloud computing model. the migration is less direct.The Definitive Guide to Cloud Computing Dan Sullivan Figure 10. and supporting cloud services are in place. When existing hardware is redeployed to the cloud. Once the hardware. applications can begin running in the cloud. Figure 10. One way to handle this challenge is to migrate applications from their dedicated servers to a set of virtual machines running on servers temporarily allocated to support the migration. applications can migrate directly to the cloud. 199 .8: Applications may be hosted on transition virtual servers in cases where existing hardware is to be redeployed to the cloud. software.7: When new hardware is deployed in the cloud. Applications are temporarily hosted on transition servers while hardware is migrated to the cloud. This approach works when servers dedicated to applications are not using the full capacity of servers.
billing periods. No service catalogs to establish and manage. and compensation for failure to meet agreements. the cost of such services. A number of essential management tasks should be in place before the cloud is widely used in the enterprise: • • • Tracking compute and storage usage for billing and cost recovery purposes Monitoring performance and load for capacity planning Auditing patterns of use and access as part of security review procedures Introducing public cloud services brings with it a different set of implementation tasks. SLAs are important for clarifying what services are expected. Adapting Public Cloud Services Using a public cloud relieves a business of many of the implementation tasks associated with private clouds. SLAs are essentially contracts between a business and a cloud provider. Instead the focus tends to be more on defining SLAs and reviewing compliance and security issues. There is no need to transition hardware or redeploy servers. SLAs with public cloud providers can include agreements about many factors: • • • • • • • • The number and types of servers that will be available for use at any time Restrictions on the number of virtual or dedicated servers that may be allocated in a single request Minimum and maximum storage usage Guaranteed bandwidth into and out of data centers used by the public cloud Security controls and procedures Audit and monitoring responsibilities of the provider and the business customer Compute and storage rates. No low‐level billing infrastructure to put in place.The Definitive Guide to Cloud Computing Dan Sullivan Management procedures must be established for maintaining the diverse array of software that will be used in the cloud. the quality of these services. These include establishing policies and procedures for: • • • • Adding and removing applications from the service catalog Patching images in the service catalog Controlling the use of licensed applications to ensure their use is in compliance with licenses Performing security reviews. such as vulnerability and malware scans on images in the service catalog A private cloud also requires a management framework for non‐software management issues. and so on Individual and aggregate demand reports 200 .
secure. 201 . probably encrypted persistent data storage in the cloud. access controls on private images or applications stored and run in the cloud. sensitivity. Using a Hybrid Private‐Public Cloud A hybrid private‐public cloud delivers the benefits of both models of cloud computing. The combined resources of a private and public cloud may appear to be seamlessly integrated from the users' perspective but there are operational differences. and confidential data is protected. This will require a combination of secure communications between the cloud data center and user sites.The Definitive Guide to Cloud Computing Dan Sullivan Several of the topics addressed in SLAs are security oriented. policies and incentives should be in place to promote the optimal balance from an enterprise perspective. Figure 10.9: If users are given a choice of where to run applications in a hybrid cloud. Only data and applications that are deemed safe to store or run in a public cloud should be made available outside the private cloud. It also brings with it the responsibilities of both that we just described—and a bit more. and verification that cloud software is routinely patched and scanned for vulnerabilities and malware. Clearly. a top priority for most businesses using public cloud services is ensuring that private.
such as user activity. For example. On a day‐to‐day basis. in fact. At this point. some of the most important operational tasks will be: • • • Monitoring Fault detection and correction Systems maintenance Cloud administrators will have to routinely monitor several attributes of a cloud. This information is also useful for prioritizing patching. as well as for long‐term capacity planning. we are in maintenance mode. Monitoring should also include security monitoring. and security controls have been put in place. management infrastructure is deployed. 202 . suspicious events—such as authentication failures or repeated unauthorized access attempts. when additional servers have to be brought online during periods of peak demand. applications are installed. This is especially important if cost recovery pricing is used and assumptions are made about the level of utilization in the private cloud. maintenance. Utilization of servers and storage capacity should be regularly monitored.1). especially when licensing costs are an issue. After that. The last key area to address for the long‐term maintenance of an enterprise cloud is. will the IT department charge an additional fee on top of the public cloud provider's charges to cover the overhead of managing the hybrid cloud? Also consider whether rules or cost structures should be in place to incentivize users to use private cloud services before turning to the public cloud. Managing and Maintaining a Cloud The tasks of managing and maintaining a cloud computing environment can be broken down into operational issues and business management issues. security scans. Operational Issues Once hardware is deployed. new business requirements will arise and will be accommodated in an incremental manner. and scanning of inbound and outbound network traffic. for example. and implementation tasks as described earlier in the discussion about the cloud computing life cycle (see Figure 10. Systems administrators should know which applications are used most frequently. The images run from the service catalog also need to be monitored. This data is useful for short‐term management. There will still be business analysis.The Definitive Guide to Cloud Computing Dan Sullivan Users of cloud services should also be made aware of any cost differences between the private and public clouds. planning. a cloud is ready to use. and upgrade planning.
organizations adopt cloud computing because it will improve the ability of the business to meet its objectives. That is the idea when the process gets started. and so on. When a storage device fails. applications running on the failed server will need to be moved to another server. the latter ensures that these are worth the effort from a business perspective. ranging from establishing value metrics to ensuring continuity of services in the event of a disaster. read and write operations should be able to continue using redundant copies of the data that was lost. In the case of a failed server. The set includes managing user identities. Changing architectures does not change the need for basic system management tasks. At the most basic level. Business Management Issues Long‐term business management issues of supporting a cloud infrastructure can be as varied as the technical issues. Aggregate data about failure rates of devices can be collected over time and provide a baseline for predicting rates of failures. but others should clearly measure the business value of the cloud. These value metrics can include generic measures such as return on investment (ROI) or more specific ones such as • • • • • Reduction in time to release a new product or service Number of CPU hours utilized for delivery business services Utilization rate of storage in the enterprise Transaction processed per unit of computing and storage resource Reduction in IT support costs per server Some value metrics should measure technical aspects. The former helps systems administrators and IT managers drive efficiencies in the cloud. and other tasks we had prior to moving to a cloud model. establishing access controls. 203 .The Definitive Guide to Cloud Computing Dan Sullivan Hardware follows the rule of large numbers: with a sufficiently large number of devices. such as server utilization rates. systems administrators will need to detect faults in servers and storage devices and be able to take those devices offline. The logic is simple: the probability of a server failing is the probability of Server A failing plus the probability of Server B failing plus the probability of Server C failing. patching software. System maintenance is a rather generic term for a broad set of tasks that one needs to perform to keep applications running as expected. some of those devices will fail and instances of failure will be more frequent for a cloud than for a single server. In a private cloud. but how do you know whether the implementation is succeeding or if you are anywhere near realizing the benefits expected? A set of value metrics need to be in place to measure the value of the cloud. such as ROI. scanning images for malware and vulnerabilities.
to high‐level design issues. network. we need to be able to answer the question. we must consider details from the lowest implementation level. Long‐term planning also requires attention to disaster recovery. Although servers may be able to fail over fairly seamlessly and redundant copies of data can be made available. For example. such as how applications manage state information. and more effective use of capital for investments. These realities provide examples where creating and maintaining lines of communications between different parts of a business are important to the long‐term effectiveness of an IT service. the programs running in the failed data center may not be as robust. albeit with some slight tuning for the unique characteristics of the cloud. if a product design group is a major user of cloud services and the company is about to acquire another firm that will significantly increase the size of the product design group. the cloud management team needs to know. 204 . Fortunately. When planning for disaster recovery. If we assume a disaster could strike and disable a data center. and an improved user experience. we can move operations to one or more alternative data centers. By aligning business objectives with the capabilities of cloud computing. businesses can realize faster time to market. If a Web application development team at a national home improvement retailer plans to provide a large number of "do it yourself" videos on the Web site and significantly increase network utilization. Maintenance and long‐term management issues in cloud environments are similar to those found in other IT environments. an application that runs for extended periods of time without writing state information to persistent storage may have to restart its processing from the beginning of a job rather than recover mid‐stream. The cloud architecture allows for more efficient utilization of infrastructure. Operational data about server. and storage utilization. Summary Cloud computing is changing the way we deliver business services. a more efficient delivery mechanism for services. numbers of business operations supported by the cloud. such as the availability of power and cooling systems. and number of users and their distribution in the company are vital for capacity planning. what happens then? If we have geographically distributed data centers with redundant storage and additional computing resources. the cloud team should be prepared.The Definitive Guide to Cloud Computing Dan Sullivan Capacity planning requires a close coupling of business planning and technology management. many of the best practices and management techniques that have evolved over the years are relevant and applicable today. For example. reduced IT support costs.
client‐server applications. or as a combination of the two. The valuable lessons learned deploying and managing mainframes. but the analysis and management principles are based on the IT industry's prior experience with other architectures and service delivery models. Download Additional eBooks from Realtime Nexus! Realtime Nexus—The Digital Library provides world‐class expert resources that IT professionals depend on to learn about the newest technologies.realtimepublishers.com. and application services. Please visit http://nexus. easy‐to‐use provisioning services. platform services. such as infrastructure providers.The Definitive Guide to Cloud Computing Dan Sullivan Cloud computing is characterized by its massive scalability. we encourage you to download more of our industry‐leading technology eBooks and video guides at Realtime Nexus. These services can be deployed according to business needs. The Definitive Guide to Cloud Computing has presented a comprehensive overview of cloud computing with a focus on identifying steps needed to successfully deploy cloud computing in your business. Technical details of cloud computing will change. publicly through a third‐party provider. and lead to improved ability to deliver current services and introduce new services without undoing encumbrance from having to deploy complex IT infrastructure. These may be delivered privately within the corporate boundaries. some adaptation. There are different levels of cloud services. with of course. 205 . and first‐generation are applicable to the cloud. If you found this eBook to be informative. and a service management platform.