snf-occi 0.3 implements the OCCI 1.1 protocol for Synnefo clouds. Since version 0.2, authentication is performed by an external keystone-compatible service, like "Astavoms". The major change is the abandonment of "snfOCCI" in favor of "OOI".
"OOI" is the Openstack OCCI Interface. It is used in snf-occi, wrapped by the newly introduced "SOI" package (Synnefo OCCI Interface). "SOI" is responsible for patching "OOI" so that it is compatible with Synnefo API.
Read the docs for more documentation, or from here: https://github.com/grnet/snf-occi/blob/master/docs/index.rst