TiKV get rolling-update when upgrade from v1.1.0.alpha.2 t v1.1.0.alpha.3

[aylei]

Bug Report

What did you do?

Upgrade tidb-operator from v1.1.0.alpha.2 to v1.1.0.alpha.3

What did you expect to see?
The running tidb-cluster does not get affected.

What did you see instead?
The running tikv statefulset gets rolling-update.

After some investigation, it turns out the new revision of TiKV statefulset has a different .spec.template.metadata.annotations.pingcap.com/last-applied-configuration compared to the old revision. The new one has securityContext: {} in the json literal, but the old one does not.

I will try to reproduce this issue and post more details.

[aylei]

The securityContext of these two revisions are different:

• new one: {}
• old one: nil

kubectl get -oyaml cannot reveal the difference because it automatically transform nil to {} for pointer to struct when marshalling YAML.