Fix issue in VolumeReplace feature that may block replacement when combined with an annotation change (#5382)

[ti-chi-bot]

This is an automated cherry-pick of #5382

What problem does this PR solve?

Fix an issue with Volume Replacement feature that can cause it to be blocked when user requests a metadata / annotation change, clubbed with a disk replacement.

What is changed and how does it work?

Remove check in pvc_replacer that checks if sts is upgrading before recreating sts.

If a disk change is clubbed with pod spec changes (but not metadata changes), it gets reverted here:

tidb-operator/pkg/manager/member/tikv_member_manager.go

Line 276 in 6de4871

newSet.Spec.Template.Spec = *podSpec

So the statefulset would not show any changes (and would not fail upgrade check, so issue doesn't happen).

However metadata changes like (annotation change), do not get reverted, and will be applied to the sts, but since volume replace marks the update strategy to be OnDelete :

tidb-operator/pkg/manager/member/tikv_member_manager.go

Line 691 in 6de4871

updateStrategy.Type = apps.OnDeleteStatefulSetStrategyType

The annotation won't be applied, and will be stuck.

Further pvc_replacer will be stuck forever on this check (which is removed in this PR)

The check itself is unnecessary since, before the code reaches here we are already in volume replace mode, which means sts should have OnDelete strategy and sts updates will only be performed by pvc_replacer clubbed with disk replace.

Code changes

• Has Go code change
• Has CI related scripts change

Tests

• Unit test
• E2E test
• Manual test
• No code

Side effects

• Breaking backward compatibility
• Other side effects:

Related changes

• Need to cherry-pick to the release branch
• Need to update the documentation

Release Notes

Please refer to Release Notes Language Style Guide before writing the release note.

Fix an issue where VolumeReplacement feature can get stuck when a disk change is clubbed with a metadata(annotation) change

[ti-chi-bot]

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[codecov-commenter]

Codecov Report

Merging #5383 (80bfc40) into release-1.5 (209d30f) will increase coverage by 0.03%.
The diff coverage is n/a.

Additional details and impacted files

@@               Coverage Diff               @@
##           release-1.5    #5383      +/-   ##
===============================================
+ Coverage        61.65%   61.69%   +0.03%     
===============================================
  Files              228      228              
  Lines            28847    28845       -2     
===============================================
+ Hits             17787    17796       +9     
+ Misses            9320     9314       -6     
+ Partials          1740     1735       -5     

Flag	Coverage Δ
unittest	61.69% <ø> (+0.03%)	⬆️