Affects Version/s: 2.6.0
Fix Version/s: None
We had a pretty major incident with the RM where it was continually flooded with RMNodeFinishedContainersPulledByAMEvents in the async dispatcher event queue.
In our setup, we had the RM HA or stateful restart disabled, but NM work-preserving restart enabled. Due to other issues, we did a cluster-wide NM restart.
Some time during the restart (which took multiple hours), we started seeing the async dispatcher event queue building. Normally it would log 1,000. In this case, it climbed all the way up to tens of millions of events.
When we looked at the RM log, it was full of the following messages:
And that node in question was restarted a few minutes earlier.
When we inspected the RM heap, it was full of RMNodeFinishedContainersPulledByAMEvents.
Suspecting the NM work-preserving restart, we disabled it and did another cluster-wide rolling restart. Initially that seemed to have helped reduce the queue size, but the queue built back up to several millions and continued for an extended period. We had to restart the RM to resolve the problem.