Performance Management of Composite Applications in Service Oriented Architectures

The use of Service Oriented Architectures (SOA) enables the existence of a market of service providers delivering functionally equivalent services at different Quality of Service (QoS) and cost levels. The QoS of composite applications can typically be described in terms of metrics such as response time, availability, and throughput of the services that compose the application. A global utility function of the various QoS metrics is the objective function used to determine a near-optimal selection of service providers that support the composite application. This chapter describes the architecture of a QoS Broker that manages the performance of composite applications. The broker continually monitors the utility of the applications and triggers a new service selection when the utility falls below a pre-established threshold or when a service provider fails. A proof-of-concept prototype of the QoS broker demonstrates how it maintains the average utility of the composite application above the threshold in spite of service provider failures and performance degradation.