CloudStack

From the Apache CloudStack Documentation:

"CloudStack is an open source software platform that pools computing resources to build public, private, and hybrid Infrastructure as a Service (IaaS) clouds. CloudStack manages the network, storage, and compute nodes that make up a cloud infrastructure. Use CloudStack to deploy, manage, and configure cloud computing environments."

DOCUMENTATION

• Using XenServer on Apache CloudStack from the Apache CloudStack documentation
• CloudStack Wikipedia entry