Cloud Computing Interoperability : An overview

At present, cloud computing has attracted a serious deal of research interest and attention in multiple domains. One of the core challenges in this environment is to achieve interoperability among heterogeneous cloud service providers (heterogeneous resources, APIs (Application Programming Interface), SLA(Service-level agreement) policy, etc.) to keep up with the increasing demand of cloud services and the growing requirements of user’s applications. For that, we provide in this paper an overview of the existing approaches and proposed solutions. In this setting, we aim to clarify: Who has posed the Cloud Computing Interoperability (CCI) problem? What does CCI mean? When and Why CCI is needed? Where does CCI problem arise? And the key question that is: How to resolve CCI problem? For this latter, we propose a taxonomy where we distinguish between the considered factors before resolving the CCI problem, and the obtained characteristics of the proposed solutions after resolving the CCI problem. Then we study existing works of CCI according to this proposed taxonomy, where we have generated three graphs allowing us to discuss CCI solution approach VS consumer-centric, CCI solution architecture VS consumer-centric, and CCI solution approach VS CCI solution type. We have concluded that: 1) the application service model is more highlighted in the literature then the management and platform levels, 2) the provider-centric solutions use generally model based approaches and are deployed as middleware or brokers, 3) the user-centric solutions are based on the adapting methodologies and deployed as brokers, 4) the hybrid solutions are based on the adapting methodologies and offer standard or broker architectures, 5) the type of CCI solution in model based approaches is mainly corresponding to framework products, 6) the final product of adapting methodologies can be a service or a library type.