we're also using cinder from openstack ocata release.
the point is
a) we didn't upgrade, but started from scratch with ceph 12
b) we didn't test all of the new features in ceph 12 (eg. EC pools for
RBD devices) in connection with cinder yet
We are live on librbd1-12.2.1 for a
week. All works okay.
I was upgraded ceph from 11.2.0 to 11.2.1. Not Luminous, because seems
12.2.1 is stable only when cluster started from Luminous
(
http://lists.ceph.com/pipermail/ceph-users-ceph.com/2017-November/022522....).