Towards adaptive management of QoS-aware service compositions

Service compositions enable users to realize their complex needs as a single request. Despite intensive research, especially in the area of business processes, web services and grids, an open and valid question is still how to manage service compositions in order to satisfy both functional and non-functional requirements as well as adapt to dynamic changes. This article describes an approach towards adaptive management of QoS aware service compositions. This approach integrates well known concepts and techniques and proposes various execution strategies based on dynamic selection and negotiation of services included in a service composition, contracting based on service level agreements, service enactment with flexible support for exception handling, monitoring of service level objectives, and profiling of execution data. An important element of the approach is an open architecture for adaptive service composition management. Its first prototypical implementation has been developed within an EU-funded Adaptive Service Grid project.