Last Friday, the OpenNebula project announced the implementation of the OGF OCCI draft specification.  The release, that will be part of OpenNebula 1.4,  includes a server implementation, clients command for using the service and enabling access to the full functionality of the OCCI interface, and several supporting documents. The last version of this open source toolkit for cloud computing, available for download in beta release, also brings libvirt, EC2 Query API, and a powerful CLI, and all of them can be used on the same OpenNebula instance, so users can use their favorite interface. In fact, OpenNebula brings support to develop other Cloud interfaces. Moreover all those interfaces can be used on any of the virtualization technologies supported, Xen, KVM and VMware.

The Open Grid Forum (OGF) Open Cloud Computing Interface  (OCCI) Working Group was officially launched in April 2009 to deliver an interface specification for managing cloud infrastructure services, also known as Infrastructure as a Service or IaaS. This specification is being driven by the requirements in several use cases. The document Requirements and Use Cases for a Cloud API records the needs of IaaS Cloud computing managers and administrators in the form of Use Cases.

In the last days there has been an intensive discussion on the topic of IaaS Cloud interfaces. There are now three main players in the arena, the Amazon EC2 API, supported by the most well-known cloud computing provider, the VMware vCloud API, supported by the leader in virtualization and submitted to DMTF, and the OGF OCCI API, being defined by an open community in the Open Grid Forum. OpenNebula now implements two of them, EC2 and OCCI, and there is interest in the OpenNebula community in implementing the third interface, vCloud (after all, OpenNebula 1.4 supports VMware). However, the interest of OpenNebula as open-source community is not only to implement an interface specification controlled by a company, but also to contribute to its definition by providing feedback and playing an active role in subsequent versions. In this sense,OCCI-WG is the only open standard sanctioned by a standards body.

While some existing open-source technologies are just implementations of commercial products and interfaces, others open-source technologies, such as OpenNebula, are powerful tools for innovation. A Cloud technology should not only be the implementation of an interface, standardized or not. OpenNebula, as technology being developed in the context of RESERVOIR European flagship project in cloud computing, provides many unique capabilities for the scalable and efficient management of the data center infrastructure. Those are the real differentiation in the cloud and virtualization market.