federated architecture in cloud systems

Discuss in 500 words or more federated architecture in cloud systems. Remember that this is a cloud class, not a database class.

Cite your sources. Do not copy. Write in essay format, not in bulleted, numbered, or another list format. 

It is important that you use your own words, that you cite your sources, that you comply with the instructions regarding the length of your post, and that you reply to two classmates in a substantive way (not 'nice post' or the like).  Your goal is to help your colleagues write better. Do not use spinbot or other word replacement software. It usually results in nonsense and is not a good way to learn anything. Please do not use attachments unless requested.