Fault-tolerant, Scalable, Wide-Area Internet Service Composition

• Authors: Z. M Mao;Randy H. Katz;Eric A. Brewer
• Venue: Fault-tolerant, Scalable, Wide-Area Internet Service Composition
• Year: 2001

As the Internet rapidly evolves, a growing number of Web services begins to emerge, and the demand for accessing them through extremely diverse end devices increases. Furthermore, a need to create novel functionality (e.g., personalized speech-enabled mailbox) by composing existing services is growing. This presents an emerging opportunity for a middleware service that, given end-point specifications and desired QoS metrics, automatically composes services in a fashion similar to plugging together tinkertoy-like elements to allow service access through heterogeneous devices and networks. Services in our context are any strongly-typed, network-, and programmatically accessible applications. In this report, we present the architectural design of such a system, the implementation and performance evaluation of a prototype. We identify the key requirements of a service composition platform: automation, scalability, and fault-tolerance. We achieve these goals through use of cluster computing platforms, identification of common patterns of ad-hoc, application-specific compositions, classification of services into a strongly typed system, redundant control mechanisms for monitoring and recovery, and a continuous optimization process with feedback. One important contribution of our work is to enable creation of new functionality from existing services with minimal effort. In addition to service reuse, our system also achieves good resource utilization in the wide area by strategically placing and locating services and dynamically adapting to resource variations. We prove its usability by demonstrating the ease with which novel functionality results from existing services and good scaling performance of the system.