Vault goes into hook error if mysql is unavailable

[David Ames]

Unfortunately, update-status runs several reactive handlers which are invasive and fail if mysql is temporarily unavailable.

Specifically any function that eventually attempts vaultclient.auth_approle() will throw an exception if mysql is unavailable.

During mysql topology changes, pause/resumes or even rolling restarts this can put the vault charm into an error state necessarily.

TRIAGE:
Make the vault charm more robust to temporary mysql unavailability.
Make the workload status indicate to the end user when this occurs.

[David Ames (thedac)]

Changed here: https://review.opendev.org/#/c/739129/

[Dariusz Smigiel (smigiel-dariusz)]

Hey David,
I think we should leave this milestone as 20.08. Initial bugfix, which you referred to in your gerrit review, has been released as 20.08.
However, there is separate bugfix: https://review.opendev.org/c/openstack/charm-vault/+/775453 which is only included in master branch, and it is not a part of any release yet.
The problem is, its commit message refers to current bug.

My recommendation would be:
1. revert the milestone of this bug back to 20.08
2. Separate #1918718 and this bug, by removing "duplicate" tag.
3. Use #1918718 as a bucket for bugfix https://review.opendev.org/c/openstack/charm-vault/+/775453

Possible problem:
1. commit message for gerrit review refers to current bug, not #1918718, so we can loose some traceability.

Possible gains:
1. By separating those two bugs, we can easily separate milestones as well.

What do you think?
Dariusz