The term Cloud Federation is heavily misused to denote a lot of different meanings. In reality, cloud federation has a simple meaning. It means that the functions and resources of two geographically different clouds are completely available to each other. Consistency and access controls are managed when two or more independent geographically distributed clouds share authentication, files, computing resources, control structures or access to storage resources. This means that the right information must flow from one cloud to the other and vice-versa.
What happens in a Federated Cloud?
In a federated cloud, the boundary between two clouds is always present. But, the elements of the boundary which prevent the interoperability of two clouds are removed. The relevancy and visibility depend on who is doing what kind of action to complete a task. For a simple business user trying to access files in a cloud environment (like One-Drive), the process is completely hidden and seamless. They will be unaware that the cloud federation is in effect. If an administrator is trying to share compute resources from one cloud with storage resources to another remote location of the enterprise, then the cloud federation boundary will require a lot of tasks. In both cases, cloud federation is apparent but the boundaries are not.
Federated Cloud Opportunities
It should be clear that federation is not achieved by connecting two different clouds with a piece of wire. The heterogeneity of clouds poses a challenge for cloud federation. However, it also brings in a lot of opportunities with increased flexibility and choice. This allows specialist variations of cloud features and behaviors, performance levels, pricing differentials, competition, cooperation, and possibilities of a rich cloud ecosystem. A homogeneous cloud federation can be built out of one and only one kind of technology. This might work. But, there’s no guarantee it will work as well as a heterogeneous cloud federation in addressing different cloud usage scenarios.