Comment 0 for bug 1769196

When removing a cinder-ceph storage backend relation we ended up with a env var override for the cinder service that referenced the non-existing ceph authx key from cinder-ceph

Detail:

1. Pre-existing cinder service configured for rbd backend

2. Added a cinder-ceph service foo-storage and relate to cinder

3. Removed relation cinder - cinder-ceph

This reconfigured the original rbd backend in cinder.conf, however it left an override for ceph authx behind:

cat /etc/init/cinder-volume.override
env CEPH_ARGS="--id foo-storage"

As the foo-storage key doesn't exist at this point the cinder-volume service errored out with (redacted):

2018-05-04 14:22:19.576 4010160 ERROR cinder.volume.manager [req-fd6ff4fd-f041-47c7-a2da-144ea353fef9 8bb46780e82b40c594476a7609b1b88f 5f182a7b537a4aa7b40832ed4bbbfbed - - -] Driver initialize connection failed (error: Unexpected error while running command.
Command: ceph mon dump --format=json --id cinder --cluster ceph
Exit code: 1
Stdout: u''
Stderr: u'2018-05-04 14:22:19.561548 7ff990749700 -1 auth: unable to find a keyring on /etc/ceph/ceph.client.foo-storage.keyring: (2) No such file or directory\n2018-05-04 14:22:19.561560 7ff990749700 -1 monclient(hunting): ERROR: missing keyring, cannot use cephx for authentication\n2018-05-04 14:22:19.5
61562 7ff990749700 0 librados: client.foo-storage initialization error (2) No such file or directory\nError connecting to cluster: ObjectNotFound\n').

Afaict those env settings are done on ceph-relation-changed in set_ceph_env_variables()