Abstract
Service Level Agreements (SLA) is the principal means of control which defines the Quality of Service (QoS) requirements in cloud computing. These requirements have to be guaranteed in order to avoid costly SLA violations. However, elasticity strategies, which have not been deeply considered yet in SLA documents, may significantly ameliorate the QoS. Therefore, in this paper, our aim is to guarantee the QoS by introducing the semantic meaning of the elasticity strategies in SLA. In this regard, we propose an ontology-based elasticity approach which allows getting an elastic cloud service by dynamically apply corrective actions. These corrective actions present the elasticity strategies applied following a violation or in prediction of a violation. Our proposed approach allows getting an interactive and flexible SLA document in order to maintain a reliable QoS and respect the SLA parameters.