Automating Composite SLA Management Tasks by Exploiting Service Dependency Information

According to the Internet of Services vision, composite services are created by composing services to complex business processes. The relationships between services in a composition are defined by Service Level Agreements (SLAs). Managing composite SLAs is a complex task which is currently performed manually. In this paper we present an approach for automating the management of composite SLAs by exploiting the explicit knowledge about dependencies between composed services. We define a formal model for representing a set of dependencies. A set of algorithms exploits this information to automate tasks of composite SLA management. These tasks are the validation of SLAs during negotiation, the evaluation of SLA renegotiation requests and the evaluation of SLA violations with regard to their effects on other services. We have validated our approach based on a logistics scenario. We present results with respect to performance and a set of test cases demonstrating the added value of dependency information based automated SLA management.