Hi Chengen,
Additionally, and back to the testing comments (sorry for the delay),
your test plan looks good, thanks! I just updated step 6 to reflect
it should fail (depending on scenario 1 or 2 / config option value).
Thanks!
** Description changed:
[Impact]
Deleting a volume will fail if it has snapshot or volume children, resulting
in an ImageBusy error.
[Fix]
Upstream has a patch that uses RBD flatten operations to break dependencies
between volumes and snapshots, reducing failures when using RBD volume clones
and snapshots.
commit 1a675c9aa178c6d9c6ed10fd98f086c46d350d3f
Author: Eric Harney <ehar...@redhat.com>
CommitDate: Fri Dec 1 10:17:05 2023 -0500
RBD: Flattening of child volumes during deletion
[Test Plan]
Here are the common steps for testing.
1. Prepare an OpenStack environment with cinder-ceph
2. Create a volume named "vol"
openstack volume create --image jammy --size 10 vol
3. Create a snapshot of the volume "vol"
openstack volume snapshot create --volume vol vol-snap
4. Create a volume named "vol-copy" from the snapshot
openstack volume create --snapshot vol-snap vol-copy
5. Delete the snapshot and then delete the volume "vol"
openstack volume snapshot delete vol-snap
openstack volume delete vol
6. Confirm that the volume "vol" is successfully deleted
+ or deletion failed (depending on the two scenarios below)
openstack volume list
There are two test scenarios:
- Enable RBD flatten operations:
1. Use `juju ssh` to log in to the cinder-volume and add
"enable_flatten_children_deletion = True" in the cinder-ceph section of
/etc/cinder/cinder.conf.
2. Restart the cinder-volume service using the command `systemctl restart
cinder-volume`.
3. Follow the common steps, and all steps should pass.
- Disable RBD flatten operations:
1. Ensure that "enable_flatten_children_deletion = True" is not present in
the cinder-ceph section of /etc/cinder/cinder.conf.
2. Follow the common steps, and the process should fail at step 5 with an
ImageBusy error.
[Where problems could occur]
The patch primarily modifies the workflow for volume deletion when using RBD
as the backend and adds a retry mechanism for unprotecting snapshots during
snapshot deletion.
To prevent any performance regressions, we have also introduced a
configuration option to enable the RBD flatten operations, which defaults to
false.
If the patch has any undiscovered issues, it will only affect volume
deletion. Other functionalities or non-RBD backends will not be impacted.
** Changed in: cinder (Ubuntu Jammy)
Status: In Progress => Incomplete
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https://bugs.launchpad.net/bugs/1969643
Title:
RBD: Unable to delete a volume which has snapshot/volume children
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