Cyril Rohr
Cyril Rohr.

The Open Cloud Computing Interface


The people behind the OCCI working group are trying to define a standard for cloud computing. The OCCI spec went from being an Infrastructure as a Service specification (i.e. how to represent compute, network, and storage resources) to a “Protocol and API for all kinds of Management tasks”. The quote below is taken from the OCCI website:

OCCI was originally initiated to create a remote management API for IaaS model based Services, allowing for the development of interoperable tools for common tasks including deployment, autonomic scaling and monitoring. It has since evolved into a flexible API with a strong focus on integration, portability, interoperability and innovation while still offering a high degree of extensibility. The current release of the Open Cloud Computing Interface is suitable to serve many other models in addition to IaaS, including e.g. PaaS and SaaS.

Well, buzzwords everywhere!

I admire the work to propose a standardized protocol for managing things, but I think it needs a lot more work to make it usable and understandable. They basically went from a simple to understand data model to a fully extensible one, which allows everything to be described (with the Resource entity), categorized (Mixin, Kind concepts), interlinked (Link entity), and managed (Action). The OCCI Core spec is unclear in many aspects, and the proposed RESTful HTTP Rendering spec is not good as it is now (my thoughts here).

There is, however, the OCCI Infrastructure spec, which as far as I can see is an instance of the OCCI Core spec targeted at IaaS providers (the original target of OCCI efforts). The spec is clear (most probably because it manipulates well understood concepts), but implementation is still dependent of the HTTP Rendering spec, which leads to inconsistent and/or broken implementations between IaaS providers.

Hopefully, that will change in the future with additions to the spec, testing tools to check the conformance of implementations, and more reference examples in major IaaS providers (OpenNebula for example).