Scenarios we should handle but missed in 2.4 for barrier execution mode

irashid You mentioned that there are couple scenarios we should handle in barrier execution mode but we didn't in 2.4. Could you elaborate here?

One scenario we are aware of is that speculation is not supported by barrier mode. Hence a barrier mode might hang in case of hardware issues on one node. I don't have a good proposal here except letting users set a timeout for the barrier stage. Would like to hear your thoughts.

You also mentioned multi-tenancy issues. Could you say more?

cc: jiangxb1987