Improving Scalability of Software Cloud for Composite Web Services

Most of the work on cloud scalability has focused on the granularity of applications and systems deployed on the cloud and on how to adjust their resource assignment according to the scale or volume of the requests. In this paper, we present a scheme for improving the scalability of service-based applications in a cloud from the granularity of the constituent services and their individual placement in the cloud. The approach we take is to analyze the communication patterns among the service operations of service-based applications and to analyze the assignment of the involved services to the available servers. We define a notion of scalability for service-based applications in a cloud and a framework to measure the scalability. We then propose an optimized assignment strategy to improve the scalability of composite Web services in terms of the productivity of such services. We report preliminary simulation experimental results that show the effectiveness of our scheme.