OK, /var/log/ovirt-engine/cinderlib/cinderlib.log says:
2019-04-01 11:14:54,925 - cinder.volume.drivers.rbd - ERROR - Error connecting to ceph cluster. Traceback (most recent call last): File "/usr/lib/python2.7/site-packages/cinder/volume/drivers/rbd.py", line 337, in _do_conn client.connect() File "rados.pyx", line 885, in rados.Rados.connect (/home/jenkins-build/build/workspace/ceph-build/ARCH/x86_64/AVAILABLE_ARCH/x86_64/AVAILABLE_DIST/centos7/DIST/centos7/MACHINE_SIZE/huge/release/12.2.11/rpm/el7/BUILD/ceph-12.2.11/build/src/pybind/rados/pyrex/rados.c:9785) OSError: [errno 95] error connecting to the cluster 2019-04-01 11:14:54,930 - root - ERROR - Failure occurred when trying to run command 'storage_stats': Bad or unexpected response from the storage volume backend API: Error connecting to ceph cluster.
I don't really know what to do with that either. BTW, the cinder version on engine host is "pike" (openstack-cinder-11.2.0-1.el7.noarch) Not sure if the version is related (I know it's been tested with pike), but you can try and install the latest rocky (that's what I use for development)
Shall I pass "rbd_secret_uuid" in the driver options? But where is this UUID created? Where is the ceph secret key stored in oVirt? I don't think it's needed as ceph based volumes are no longer a network disk like in the cinder integration, but it is attached like a regular block device The only things that are a must now are "rbd_keyring_conf" and "rbd_ceph_conf" (you don't need the first if the path to the keyring is configured in the latter) And I think you get the error because it's missing or incorrect, since I manually removed the keyring path from the configuration and got the same error as you