Nimbus is cloud computing for science.
Nimbus Platform
is an integrated set of tools that deliver the power and
versatility of infrastructure clouds to scientific users.
Nimbus Platform allows you to combine Nimbus, OpenStack,
Amazon, and other clouds.
Nimbus Infrastructure
is an open source EC2/S3-compatible
Infrastructure-as-a-Service implementation specifically
targeting features of interest to the scientific community
such as support for proxy credentials, batch schedulers,
best-effort allocations and others.