Enforcing SLAs in Scientific Clouds

Software as a Service (SaaS) providers enable the on-demand use of software, which is an intriguing concept for business and scientific applications. Typically, service level agreements (SLAs) are specified between the provider and the user, defining the required quality of service (QoS). Today SLA aware solutions only exist for business applications. We present a general SaaS architecture for scientific software that offers an easy-to-use web interface. Scientists define their problem description, the QoS requirements and can access the results through this portal. Our algorithms autonomously test the feasibility of the SLA and, if accepted, guarantee its fulfillment. This approach is independent of the underlying cloud infrastructure and successfully deals with performance fluctuations of cloud instances. Experiments are done with a scientific application in private and public clouds and we also present the implementation of a high-performance computing (HPC) cloud dedicated for scientific applications.