New Pricing Policies for Federated Cloud

In Cloud computing, resources such as CPU, RAM, and disk etc. are provided as a service via the Internet. Elasticity is a key feature of Cloud Computing. It aims to enabling a Cloud Service Provider (CSP) to negotiate the possibility to borrow external resources from other CSPs when its own facilities are not able to satisfy a client request. Reciprocally, a CSP may sell some of its unused resources to another CSP in case of under load. Today, Cloud Brokering and Cloud Federation are the two approaches considered for Cloud elasticity. In the context of the Easi-Clouds European ITEA 2 research project, we aim to develop Pricing-as-a-Service (PraaS) suited to Federated Cloud environment. The aim of this paper is twofold. First, we provide a state of the art of pricing in multi-cloud environment. We discuss specifications of Cloud Brokering and Cloud Federation. Three types of pricing strategies (on-demand, spot and reserved) are presented with different existing resource pricing models. In the second part we propose different pricing policies suited to the Federated environment with numerical analysis via simulation. Finally, results are provided showing the best pricing policy suited for federation cloud as well as the spot influence on a federated environment. Results are evaluated in term of CSPs revenues and the number of rejected sessions.