JOpera: Autonomic Service Orchestration

The increasing interest in new software engineering technologies for application integration such as Service Oriented Computing and Service Orchestration has resulted in a proliferation of workflow management systems as the underlying representation and execution platform for service composition [7]. Workflow management system are also being applied to new domains (e.g., virtual scientific laboratories [1], Grid computing [12], service delivery and provisioning [6]). For these new applications, workflows are seen as the modeling metaphor behind the notion of straight through processing and virtual organizations where a collection of existing heterogeneous systems are composed into an integrated solution. In all these settings workflow engines are at the core of a complex combination of applications and clustered computers. As such, they have become rather difficult to deploy and configure, let alone tune to obtain maximum performance. This problem is not unique to workflow and service composition engines but it is more difficult to address in these settings because there is only a limited understanding of the execution procedures behind a workflow engine. In this short paper we report on our ongoing work to design and develop an autonomic workflow engine that can be used for large scale service composition. The challenge we face in doing this is threefold. First, we need to design an execution procedure for service compositions that is amenable to autonomic treatment. Second, this procedure needs to be realized in an architecture that supports the deployment of different modules of the system across a computer cluster in order to achieve the desired level of performance. Third, an autonomic controller and appropriate control policies need to be developed to automatically provision the optimal amount of resources to the engine. In what follows we provide a high level description of how we have accomplished these three goals and give a brief account of the performance of the system. The implemented system is part of the JOpera project. JOpera is an advanced SOA tool for Eclipse, which provides modeling, execution, monitoring and debugging tools for workflow-based Web service orchestration. A more detailed presentation of the autonomic capabilities of JOpera, including an extensive experimental evaluation of the approach can be found in [4, 11].