[druid-user] Update error

All,

We try to upgrade our druid cluster from 0.22.1 to 023.0. After
upgraded, All panels of web console worked fine except tasks lists.
There was an error message in the tasks panel:

'Unknown exception / Failed to talk to leader node at
[/druid/indexer/v1/tasks]. Error code[500], description[Server Error].
/ org.apache.druid.java.util.common.RE'

Because it is a production system, I have to rollback to 0.22.1 and
everything back to normal.

Does anyone have an idea of what was wrong? Where should I check? I
did not make any configuration changes.

Thank you!

Jun

If you check overlord logs, is any overlord becoming leader? If not, is there an error message about why?

Or I should say, was any overlord becoming leader. Do you still have logs that contain entries from the time of upgrade?

Also, do you have custom log4j configuration? I just saw that causing an issue on Apache druid slack (here).