STRATFram: A framework for describing and evaluating elasticity strategies for service-based business processes in the cloud

International audienceIn the recent years, growing attention has been paid to the concept of Cloud Computing as a new computing paradigm for executing and handling operations/processes in an efficient and cost-effective way. Cloud Computing’s elasticity and its flexibility in service delivery have been the most important features behind this attention which encourage companies to migrate their operation/processes to the cloud to ensure the required QoS while using resources and reduce their expenses. Elasticity management has been considered as a pivotal issue among IT community that works on finding the right tradeoffs between QoS levels and operational costs by developing novel methods and mechanisms. However, controlling process elasticity and defining non-trivial elasticity strategies are challenging issues. Also, despite the growing attention paid to the cloud and its elasticity property in particular, there is still a lack of solutions that support the evaluation of elasticity strategies used to ensure the elasticity of processes at service-level. In this paper, we present a framework for describing and evaluating elasticity strategies for Service-based Business Processes (SBP), called StratFram. It is composed of a set of domain-specific languages designed to generalize the use of the framework and to facilitate the description of evaluation elements that are needed to evaluate elasticity strategies before using them in real cloud environment. Using StratFram, SBP holders are allowed to define: (i) an elasticity model with specific elasticity capabilities on which they want to define and evaluate their elasticity strategies, (ii) a SBP model for which the elasticity strategies will be defined and evaluated, (iii) a set of elasticity strategies based on the elasticity capabilities of the defined elasticity model and for the provided SBP model, and (iv) a simulation configuration which identifies simulation properties/elements. The evaluation of elasticity strategies consists in providing a set of plots that allows the analysis and the comparison of strategies. Our contributions and developments provide Cloud tenants with facilities to choose elasticity strategies that fit to their business processes and usage behaviors