On Verifying and Assuring the Cloud SLA by Evaluating the Performance of SaaS Web Services across Multi-Cloud Providers

Software-as-a-service (SaaS) cloud web services are delivered by cloud providers to cloud customers on a pay-peruse model. Service level agreements (SLAs) are used to define the quality of the provided services. Unfortunately, there is no standard mechanism or an automatic way which exist to verify and assure that delivered services satisfy the signed SLA agreement and impede the possibility to measure accurately the Quality of Service (QoS). In this abstract, we offer a framework of steps to verify and assure the SLA compliance of Web Services offered across several Cloud providers. Our framework targets also the evaluation of the QoS of the SaaS Web Services (WSs). In this context, our framework aims at quantifying in a fair and by stealth way the performance and scalability of the delivered WS. The framework defines a set of Common performance metrics handled by a set of agents for measuring the behaviour of cloud applications on top of a given CSP. The premier results from this framework are summarized by the performance metrics monitoring, modelling and sensitivity analysis of the models' parameters. This framework opens novel perspectives for assessing the SLA compliance of Cloud providers and QoS evaluation.