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https://issues.apache.org/jira/browse/YARN-4133?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
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zhihai xu updated YARN-4133:
----------------------------
Attachment: (was: YARN-4133.000.patch)
> Containers to be preempted leaks in FairScheduler preemption logic.
> -------------------------------------------------------------------
>
> Key: YARN-4133
> URL: https://issues.apache.org/jira/browse/YARN-4133
> Project: Hadoop YARN
> Issue Type: Bug
> Components: fairscheduler
> Affects Versions: 2.7.1
> Reporter: zhihai xu
> Assignee: zhihai xu
> Attachments: YARN-4133.000.patch
>
>
> Containers to be preempted leaks in FairScheduler preemption logic. It may
> cause missing preemption due to containers in {{warnedContainers}} wrongly
> removed. The problem is in {{preemptResources}}:
> There are two issues which can cause containers wrongly removed from
> {{warnedContainers}}:
> Firstly missing the container state {{RMContainerState.ACQUIRED}} in the
> condition check:
> {code}
> (container.getState() == RMContainerState.RUNNING ||
> container.getState() == RMContainerState.ALLOCATED)
> {code}
> Secondly if {{isResourceGreaterThanNone(toPreempt)}} return false, we
> shouldn't remove container from {{warnedContainers}}. We should only remove
> container from {{warnedContainers}}, if container is not in state
> {{RMContainerState.RUNNING}}, {{RMContainerState.ALLOCATED}} and
> {{RMContainerState.ACQUIRED}}.
> {code}
> if ((container.getState() == RMContainerState.RUNNING ||
> container.getState() == RMContainerState.ALLOCATED) &&
> isResourceGreaterThanNone(toPreempt)) {
> warnOrKillContainer(container);
> Resources.subtractFrom(toPreempt,
> container.getContainer().getResource());
> } else {
> warnedIter.remove();
> }
> {code}
> Also once the containers in {{warnedContainers}} are wrongly removed, it will
> never be preempted. Because these containers are already in
> {{FSAppAttempt#preemptionMap}} and {{FSAppAttempt#preemptContainer}} won't
> return the containers in {{FSAppAttempt#preemptionMap}}.
> {code}
> public RMContainer preemptContainer() {
> if (LOG.isDebugEnabled()) {
> LOG.debug("App " + getName() + " is going to preempt a running " +
> "container");
> }
> RMContainer toBePreempted = null;
> for (RMContainer container : getLiveContainers()) {
> if (!getPreemptionContainers().contains(container) &&
> (toBePreempted == null ||
> comparator.compare(toBePreempted, container) > 0)) {
> toBePreempted = container;
> }
> }
> return toBePreempted;
> }
> {code}
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