This paper describes an information system designed to support the large volume of monitoring information generated by a distributed testbed. This monitoring information is produced by several subsystems and consists of status and performance data that needs to be federated, distributed, and stored in a timely and easy to use manner. Our approach differs from existing approaches because it federates and distributes information at a low architectural level via messaging; a natural match to many of the producers and consumers of information. In addition, a database is easily layered atop the messaging layer for consumers that want to query and search the information. Finally, a common language to represent information in all layers of the information system makes it significantly easier for users to consume information. Performance data shows that this approach meets the significant needs of FutureGrid and would meet the needs of an experimental infrastructure twice the size of FutureGrid. In addition, this design also meets the needs of existing distributed scientific infrastructures.
@cite_33: The Globus Toolkit Monitoring and Discovery System (MDS4) defines and implements mechanisms for service and resource discovery and monitoring in distributed environments. MDS4 is distinguished from previous similar systems by its extensive use of interfaces and behaviors defined in the WS-Resource Framework and WS-Notification specifications, and by its deep integration into essentially every component of the Globus Toolkit. We describe the MDS4 architecture and the Web service interfaces and behaviors that allow users to discover resources and services, monitor resource and service states, receive updates on current status, and visualize monitoring results. We present two current deployments to provide insights into the functionality that can be achieved via the use of these mechanisms.
@cite_8: High-performance execution in distributed computing environments often requires careful selection and configuration not only of computers, networks, and other resources but also of the protocols and algorithms used by applications. Selection and configuration in turn require access to accurate, up-to-date information on the structure and state of available resources. Unfortunately no standard mechanism exists for organizing or accessing such information. Consequently different tools and applications adopt ad hoc mechanisms, or they compromise their portability and performance by using default configurations. We propose a Metacomputing Directory Service that provides efficient and scalable access to diverse, dynamic, and distributed information about resource structure and state. We define an extensible data model to represent required information and present a scalable, high-performance, distributed implementation. The data representation and application programming interface are adopted from the Lightweight Directory Access Protocol; the data model and implementation are new. We use the Globus distributed computing toolkit to illustrate how this directory service enables the development of more flexible and efficient distributed computing services and applications.
A number of information systems have been proposed and deployed on scientific infrastructures. For example, early versions of the Globus software included a Metacomputing Directory Service (MDS) @cite_8 for storing information in a hierarchical directory service accessed via the Lightweight Directory Access Protocol (LDAP). The Globus project then transitioned to a MDS based on web service (SOAP WSDL) technologies @cite_33 .