Transparent Access to Scientific and Commercial Clouds from the Kepler Workflow Engine

This paper describes the architecture for transparently using several di erent Cloud Resources from with the graphical Kepler Worklfow environment. This architecture was proven to work by implementing and using it in practice within the FP7 project EUFORIA. The clouds supported are the Open Source cloud environment OpenNEbula (ONE) and the commercial Amazon Elastic Compute Cloud (EC2). Subsequently, these clouds are compared regarding their cost-e ectiveness, which covers a performance examination but also the comparison of the commercial against a scienti c cloud provider.