Towards an Enactment Engine for Dynamically Reconfigurable and Scalable Choreographies

Service compositions have recently been in the spotlight. Although they are not something new, as the complexity of service based systems grows, we observe an ever increasing interest in these approaches. Choreographies are one specific kind of service composition in which the responsibilities for the execution of the system are shared by its service components without any central point of coordination. Choreography clients expect a minimum level of Quality of Service (QoS); however, due to the distributed nature of these systems, a manual approach to resource usage monitoring and allocation is not only inefficient but also does not scale. In this paper we present an open source choreography enactment engine that is capable of automatically deploying and executing a given composition. Additionally, it also monitors a composition execution to perform automatic resource provisioning and dynamic service reconfiguration based on pre-defined Service Level Agreement (SLA) constraints. We evaluated our system on Amazon EC2 and preliminary results demonstrate that it is able maintain the QoS of a composition, even when faced with varying levels of load, while at the same time reducing costs by using as little computational resources as possible.