Towards Management of Complex Service Compositions - Position Paper

Many companies offer physical products combined with on-line services. For example, product configuration, ordering, order tracking, and payments can be done on-line. The service part of the total offering (the composition) is typically composed of services offered by providers where performance of both the composition (provided by the company) and the input services (obtained from providers) is governed by service level agreements (SLAs). The goal of our approach is to diagnose the performance of an on-line service composition in terms of the performance of on-line input services, with respect to the performance indicators mentioned in the SLAs, and to do this in real-time. Classical SLA monitoring techniques are batch-oriented and are not usable in the highly dynamic environment of Web service provision, where provider relations may change even during service delivery. Our techniques use real-time analysis of log files to trace and diagnose performance on-the-fly. Current Web service monitoring techniques do not relate a composite service to its components, as needed to provide diagnostic information. Furthermore, current approaches do not take into account that the dependency of a composition on its components varies for different attributes (such as cost and response time). In this paper we propose to extend our previous research in this area by lifting a number of simplifying assumptions to make the approach applicable in real-life, and by extending our study to frequently used SLAs in practice.