[libvirt] ceps-based backing stores

I have a file with an ceph-based backing store. I run this command: nova boot vm-clone where vm-clone is the rbd-backed file. It generates this command: qemu-img create -f qcow2 -b rbd:rbdpool/disk/instance-00000002.0.disk:conf=/etc/ceph/ceph.conf:id=admin -F raw /mnt/novadisk/nova/instances/3efa8a7b-75a8-4695-8fdd-659185c46b7d/disk and I am getting this error: error: internal error: backing store parser is not implemented for protocol rbd I was under the impression that qemu could work with ceph-based backing stores, so is there something I should run first, or files that I should patch, or ... ??? I am running libvirt 1.2.9. Thanks for any assistance you can provide. Lyssa