[ovirt-users] Why rbd support is not natively available just like glusterFS?

Dear oVirt users, We are currently looking for a virtualization solution and oVirt seems to be a good choice for us. The problem is we have to deploy it on the top of a Ceph/RBD storage. Maybe I missed something but it seems Ceph/RBD block devices are not available in oVirt, just like GlusterFS. However Qemu supports it as a native storage backend. Could you explain why it is not available ? We saw Ceph storage could be usable through OpenStack Cinder in the 3.6 version but we don't want/need to deploy an OpenStack infrastructure (and we don't found complete documentation about that). Any help on this topic would be much appreciated Thank you for advance, Best regards