Chang Li created YARN-4059:
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Summary: Preemption should delay assignments back to the preempted
queue
Key: YARN-4059
URL: https://issues.apache.org/jira/browse/YARN-4059
Project: Hadoop YARN
Issue Type: Bug
Reporter: Chang Li
Assignee: Chang Li
When preempting containers from a queue it can take a while for the other
queues to fully consume the resources that were freed up, due to delays waiting
for better locality, etc. Those delays can cause the resources to be assigned
back to the preempted queue, and then the preemption cycle continues.
We should consider adding a delay, either based on node heartbeat counts or
time, to avoid granting containers to a queue that was recently preempted. The
delay should be sufficient to cover the cycles of the preemption monitor, so we
won't try to assign containers in-between preemption events for a queue.
Worst-case scenario for assigning freed resources to other queues is when all
the other queues want no locality. No locality means only one container is
assigned per heartbeat, so we need to wait for the entire cluster heartbeating
in times the number of containers that could run on a single node.
So the "penalty time" for a queue should be the max of either the preemption
monitor cycle time or the amount of time it takes to allocate the cluster with
one container per heartbeat. Guessing this will be somewhere around 2 minutes.
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