
Rackspace released the source code for OpenStack to public in 2010. The Cloud service itself is based on the Xen hypervisor and offers flexible and efficient server options for companies allowing them to offer hosted sites that are completely scalable. The service is available in both Windows and Linux versions with full root access, control panel, API, and the recently acquired Cloudkick service all available.
More than 500 customers signed up for the beta service while Rackspace has more than 100,000 customers globally.