Currently, several solution cloud computing IaaS (Infrastructure as a Service) exists. Administrators, developers and users need to choose the best environment for them. The availability of free open source Cloud platforms is essential to further drive the proliferation of private and hybrid Cloud computing environments. In this paper, the authors present a comparative study between some of the IaaS commonly used to select the best suited one for deployment and research development in the field of cloud computing. The aim is to provide the computer industry with the opportunity to build a hosting architecture, massively scalable which is completely open source, while overcoming the constraints and the use of proprietary technologies.