Eric Payne created YARN-2592:

             Summary: Preemption can kill containers to fulfil need of already 
over-capacity queue.
                 Key: YARN-2592
             Project: Hadoop YARN
          Issue Type: Bug
    Affects Versions: 2.5.1, 3.0.0
            Reporter: Eric Payne

There are scenarios in which one over-capacity queue can cause preemption of 
another over-capacity queue. However, since killing containers may lose work, 
it doesn't make sense to me to kill containers to feed an already over-capacity 

Consider the following:

root has A,B,C, total capacity = 90
A.guaranteed = 30, A.pending = 5, A.current = 40
B.guaranteed = 30, B.pending = 0, B.current = 50
C.guaranteed = 30, C.pending = 0, C.current = 0

In this case, the queue preemption monitor will kill 5 resources from queue B 
so that queue A can pick them up, even though queue A is already over its 
capacity. This could lose any work that those containers in B had already done.

Is there a use case for this behavior? It seems to me that if a queue is 
already over its capacity, it shouldn't destroy the work of other queues. If 
the over-capacity queue needs more resources, that seems to be a problem that 
should be solved by increasing its guarantee.

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