"Eucalyptus Systems has announced it will support VMware's ESX
hypervisor and vSphere 4 virtual machine infrastructure as the
foundation for a private cloud.
"The Eucalyptus version of those interfaces can be used to build
private clouds inside the enterprise capable of running virtual
machines governed by the open source Xen or KVM hypervisors.
VMware's ESX Server is the first commercial environment Eucalyptus
has chosen to support. It's also stopped short of trying to
duplicate Amazon's SimpleDB, since MySQL is commonly used in the
open source projects and environments where Eucalyptus got its