Formal Modeling and Evaluation of Service-Based Business Process Elasticity in the Cloud

Abstract

International audienceCloud computing is a new delivery model for IT services. Cloud platforms are being increasingly used for the deployment and execution of service-based business processes (SBPs). Nevertheless, the provisioning of elastic infrastructures and/or platforms is not sufficient to provide users with elasticity at the level of SBPs. Therefore, there is a need to provide SBPs with mechanisms to scale their resource requirements up and down whenever possible. This can be achieved using mechanisms for duplicating and consolidating business services that compose the SBPs. In this paper, we propose a formal model for SBPs elasticity in the Cloud. We show that our model preserves the semantics of SBPs when services are duplicated or consolidated. We also propose a formal framework for the evaluation of elasticity strategies that decide on when and how many resources are required to ensure elasticity of SBPs

Formal Modeling and Evaluation of Stateful Service-Based Business Process Elasticity in the Cloud

“…In [2] we formally proved the correctness of our elasticity mechanisms. In addition, we have provided a framework to evaluate strategies based on duplication/consolidation.…”

“…In the previous paper [2] we applied the same structural duplication and consolidation operations on classical Petri-net. We proved that this two operations preserve the structural and dynamical properties of the net modulo ≡ T and ≡ P relations.…”

“…Actually, we have introduced a generic controller for the elasticity of business processes based on stateless services [1]. In addition, we have formally described the controller and shown how it is used for the evaluation of elasticity strategies [2]. In this paper we go further in considering the elasticity of stateful SBPs.…”

A bigraphical model for specifying cloud-based elastic systems and their behaviour

“…For instance, the authors of [3] introduce a formal framework based on Petri nets to model service-based business processes (SBP) in cloud computing environments, as well as the evaluation of their elastic behaviour and elasticity strategies. In particular, the authors describe the horizontal scale elasticity method by defining two Petri nets operations for the duplication and consolidation of cloud computing services.…”

“…[15] and [16] dealt also with infrastructure level elasticity without considering a particular elasticity method. The exemption was made by [3,4,5] which capture horizontal elasticity at software level and [10] who deals with both horizontal and vertical elasticity at infrastructure and software levels. The formal specification of platform and load balancing elasticity levels and the migration elasticity method were not handled by any of these contributions.…”