Comment 9 for bug 1777123

We are using ceph luminous as a back-end. Moreover, I've catched similar problem on one computing node during unshelving procedure - nova fails to unshelve an instance with "TypeError: name must be a string" on the image restoration step. I'm currently on some kind of vacation, so I'll be able to provide log output only within several days.
I will try to dig into openstack-ansible-os_nova to get why so old rbd is get installed, as luminous ceph version had been specified in user_variables.yml (and ceph client is installed from luminous outside of virtualenv).