Eric Payne created YARN-2592:
--------------------------------
Summary: Preemption can kill containers to fulfil need of already
over-capacity queue.
Key: YARN-2592
URL: https://issues.apache.org/jira/browse/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
queue.
Consider the following:
{code}
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
{code}
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.
--
This message was sent by Atlassian JIRA
(v6.3.4#6332)
