8 Red Hat OpenShift and IBM Cloud Paks on IBM Power Systems: Volume 1
2.1  A new computing paradigm in cloud transformation
Cloud computing transformed the way that IT is managed.
In the traditional method of using services or resources, the owner of the infrastructure is 
responsible for managing every piece of hardware and software they use. Normally, it takes 
some time for a user to access a new resource, but it can be configured exactly as needed.
Traditional infrastructure is often related to aging core applications (typically integrated with 
aging infrastructure and technologies) that cannot be easily migrated to cloud paradigms. 
Elasticity, standardization, and other clear cloud advantages are not sufficient reasons to 
migrate. In other cases, rigid security and country regulations sometimes force users to locate 
data nearby and under total management control.
2.1.1  Cloud service model
This section describes the different cloud service models.
Infrastructure as a service (IaaS)
The management responsibility for the company starts with the operating system layer and 
the provider ensures the availability and reliability of the infrastructure provided.
Several use cases can benefit from this pattern. Companies that lack an owned data center 
look to IaaS as a quick, cheap infrastructure for their business initiatives that can be 
expanded or ended as needed. Traditional companies that need compute power to run 
variable workloads with less capital expenditure are perfect examples of IaaS adoption. In 
both cases, companies pay only for the services that they use.
Platform as a service (PaaS)
Development companies and factories that want to implement agile methodologies are the 
most suited for PaaS. PaaS providers publish many services that can be used inside 
applications. Those services are always available and up-to-date. PaaS provides a simple 
way to test and prototype new applications. It can save money when developing new services 
and applications. Applications can be released more quickly than usual to get user feedback.
The API economy is the new paradigm in development. The cloud provides the perfect 
platform for its implementation.
Software as a service (SaaS)
At the time of this writing, SaaS patterns are accepted by many companies that want to 
benefit from application usage without the need to maintain and update infrastructure and 
components. Mail, ERP, collaboration, and office apps are the most accepted SaaS solutions. 
The flexibility and elasticity of the SaaS model are great benefits.
No “one-size-fits-all” solution exists for cloud adoption. Companies must consider their own 
cost and benefit equation and then decide on the best model. Each application and process 
that is needed is a workload. A deep workload assessment is normally performed by 
companies that decided to move to the cloud.