Government agencies interested in building out privately-run internal clouds , will find that there are a growing number of open-source tools to help them.
Two such tools are Eucalyptus and Deltacloud. Both platforms offer a set of application programming interfaces that can serve as a front end, or a broker, to a private cloud or even a set of clouds, which would allow users to pick the best cloud service for the job.
Of the two packages, Eucalyptus is farther along in terms of development: NASA uses Eucalyptus for its Nebula cloud. The Energy Department's Argonne National Laboratory is also exploring Eucalyptus, for scientific research. Deltacloud is still in development, though agencies could participate and help define it features.
In short, Eucalyptus provides a front end that replicates the environment offered by the Amazon Web Services (AWS). The goal was to build an interface "where a user or program cannot tell the difference between Amazon and what we built," Wolski said. This project was possible because "Amazon documents its APIs very carefully," he said. Behind the APIs, Eucalyptus handles the coordination with the virtual machines, storage provisioning and networking.
Read the whole story at http://fcw.com/articles/2009/11/17/hybrid-clouds.aspx