Code-named “Carina”, the twenty-first release of OpenNebula is available today with a new innovative provisioning model based on virtual Data Centers that offers a simple but comprehensive framework for resource allocation to different groups of users in federated data centers and hybrid cloud deployments. Carina brings the ability to easily federate multiple OpenNebula clouds for high availability, scalability, isolation or multiple-site support, and the seamless sharing of golden images across these zones through a new revamped AppMarket. Users can also browse and provision services on-demand using a new simple, intuitive cloud provisioning portal.