Comment 1 for bug 1711642

I can confirm that (Ocata, 17.02 charms), one of the consequences is that you may have an incorrect secret passed to QEMU.

As a result it will fail with "process exited while connecting to monitor".

2017-08-18 13:02:47.123 13832 ERROR nova.compute.manager [instance: cd682722-6417-4df1-92b5-dd4c5215e6c7] libvirtError: internal error: process exited while connecting to monitor: 2017-08-18T13:02:46.126047Z qemu-system-x86_64: -drive file=rbd:cinder-ceph/volume-2aabe89d-6feb-44f5-8bf0-85f270546be9:id=cinder-ceph:key=AQBfjZVZ+BtmKBAAsNrqkZfDBSc/GdoufBtHPA==:auth_supported=cephx\;none:mon_host=10.44.91.10\:6789\;10.44.91.23\:6789\;10.44.91.26\:6789,format=raw,if=none,id=drive-virtio

I had to remove/add a relation between nova-compute-kvm and cinder-ceph as a workaround.

The secret was simply incorrect.