Kevin Carey, Dave Lewis, Vincent Wade

Automated Policy-Refinement for Managing Composite Services

Knowledge and Data Engineering Group
Department of Computer Science
Trinity College Dublin

From e-commerce to ubiquitous computing, service composition is seen as a key technique in rapidly generating new, tailored functionality from existing service implementations. However, within a specific composite service deployment there may still be the opportunity for further run-time adaptation of the composite service’s behaviour based on run-time adaptively built into the software components that implement. This may, for instance, cover non-functional behaviour such as quality of service. In this paper it is assumed that a implementer of service components provide runtime adaptively of service via policy rules that can be triggered by runtime events and which, given certain specified condition are satisfied, will cause specified actions to be taken by the component. Policy rules are declarative and can be loaded into a component at deployment or runtime. However, rules for specific service components will use terminology native to that service and so coordinating the aggregate adaptive behaviour of a composite service though manipulating the heterogeneous policy rules of the components implementing its constituent service is potentially complex. This paper describes an approach to automatically managing constituent service policyrules of a composite service based. This management allows an administrator or a user to assign a goal, in the form of a high-level policy with event, condition and action, for the composite service and ensures that this goal is propagated to the constituent services by refining this goal into policies which are executed upon the service implementation. The approach taken exposes a service implementation’s management controls as a finite state machine (FSM).