SPACE4CLOUD: A Tool for System PerformAnce and Cost Evaluation of CLOUD Systems

Cloud Computing is assuming a relevant role in the world of web applications and web services. Cloud technologies allow to build dynamic systems which are able to adapt their performance to workload fluctuations delegating to the Cloud Provider the intensive tasks of management and maintenance of the cloud infrastructure. Which is the best provider for our application? The application will guarantee the required service level objectives (SLOs)? Those are relevant issues that call for a tool able to carry on cost and performance analysis of the system before its actual development. In designing a software application to be executed in a cloud environment, the most relevant issues to be addressed are determining which cloud provider to use and verifying if the target system will present the required performance levels. The goal of this work is to provide a model-driven approach to performance and cost estimation of cloud and multi-cloud systems. We considered the IaaS (Infrastructure-as-a- Service) and PaaS (Platform-as-a-Service) levels. The modelling of such systems has involved different abstraction levels, starting from the representation of cloud applications and ending with the modelling of the underlying insfrastructure/platform belonging to specific Cloud Providers. An initial prototype supporting our approach is also presented