Private Clouds provide many of the benefits of the Public Cloud, namely elastic scalability, faster time-to-market and reduced OpEX, all within the Enterprises own perimeter that complies to its governance. Leading commercial Private Cloud products include VMware, Univa UD, Unisys. Open source solutions include pro ducts like Globus Nimbus, Enomaly Elastic Computing Platform, RESERVOIR and Eucalyptus.

Read more at: http://bigdatamatters.com/bigdatamatters/2009/09/private-cloud-eucalyptus.html