When the cinder-backup service is deployed, the service is not being configured with any of the THT parameters. Instead, it ends up running with an entirely default configuration (which happens to use the swift backend driver).
The problem can be observed by deploying cinder-backup, and checking the backup_driver setting in the DEFAULT section of cinder.conf. TripleO should always configure the backup_driver, even when using swift (the default swift). In other words, when the backup service is deployed, the backup_driver should never be left commented out.
No doc text required. This was a regression introduced and fixed in stein prior to the release of OSP-15.
Deployed Cinder backup service via adding on overcloud_deploy.sh ->
--environment-file /usr/share/openstack-tripleo-heat-templates/environments/cinder-backup.yaml \
255 # Driver to use for backups. (string value)
256 #backup_driver = cinder.backup.drivers.swift.SwiftBackupDriver
As seen above this happens to be an LVM deployment defaults to swift as Cinder backup any way.
But line 257 the backup_driver is present not commented out.
On another deployment this time with a later THT, deployed with ceph
260 # Driver to use for backups. (string value)
261 #backup_driver = cinder.backup.drivers.swift.SwiftBackupDriver
backup_driver was never commented out, looks OK to verify.
Since the problem described in this bug report should be
resolved in a recent advisory, it has been closed with a
resolution of ERRATA.
For information on the advisory, and where to find the updated
files, follow the link below.
If the solution does not work for you, open a new bug report.