Multi-Cloud

Using resources and services from multiple Clouds is a natural evolution from consuming the ones from in-silo Clouds. Technological and administrative barriers are however slowing the process. Fortunately the recent years are marked by the appearance of several solutions that are partially overpassing them. However, the approaches are quite various and not adopted at large scale. This paper intends to offer a snapshot of the current state-of-the-art and to identify the future steps in building Multi-Clouds. A list of basic requirements for a Multi-Cloud is proposed.