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https://issues.apache.org/jira/browse/YARN-4676?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15274847#comment-15274847
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Daniel Zhi commented on YARN-4676:
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8. The method "private int refreshNodes(int timeout)" inside RMAdminCLI is the
client-side logic that periodically checks and finally forceful decommission
nodes if timeout. With this JIRA, the same timeout is also handled by RM
server-side where the nodes will be decommissioned automatically upon timeout.
The extra gracePeriod (now reduced to 5 seconds) here is to wait a little
longer so to avoid unnecessary double decommission upon timeout from the
client-side. In your example where user ask for 20 seconds, RM server-side will
decommissioned the node no later than 20 seconds, the client will then notice
the node become DECOMMISSIONED and simply finish without forceful decommission.
25. I will leave the evaluation of "disallow and exit" under "work preserving
restart" for proper decision makers to make separately. The code pre this patch
already allow graceful decommission (from client side) regardless "work
preserving restart". It's better that I don't prematurely change it now. It
could be addressed in as part of separate JIRA early comments conclude.
> Automatic and Asynchronous Decommissioning Nodes Status Tracking
> ----------------------------------------------------------------
>
> Key: YARN-4676
> URL: https://issues.apache.org/jira/browse/YARN-4676
> Project: Hadoop YARN
> Issue Type: Sub-task
> Components: resourcemanager
> Affects Versions: 2.8.0
> Reporter: Daniel Zhi
> Assignee: Daniel Zhi
> Labels: features
> Attachments: GracefulDecommissionYarnNode.pdf,
> GracefulDecommissionYarnNode.pdf, YARN-4676.004.patch, YARN-4676.005.patch,
> YARN-4676.006.patch, YARN-4676.007.patch, YARN-4676.008.patch,
> YARN-4676.009.patch, YARN-4676.010.patch, YARN-4676.011.patch,
> YARN-4676.012.patch, YARN-4676.013.patch
>
>
> YARN-4676 implements an automatic, asynchronous and flexible mechanism to
> graceful decommission
> YARN nodes. After user issues the refreshNodes request, ResourceManager
> automatically evaluates
> status of all affected nodes to kicks out decommission or recommission
> actions. RM asynchronously
> tracks container and application status related to DECOMMISSIONING nodes to
> decommission the
> nodes immediately after there are ready to be decommissioned. Decommissioning
> timeout at individual
> nodes granularity is supported and could be dynamically updated. The
> mechanism naturally supports multiple
> independent graceful decommissioning “sessions” where each one involves
> different sets of nodes with
> different timeout settings. Such support is ideal and necessary for graceful
> decommission request issued
> by external cluster management software instead of human.
> DecommissioningNodeWatcher inside ResourceTrackingService tracks
> DECOMMISSIONING nodes status automatically and asynchronously after
> client/admin made the graceful decommission request. It tracks
> DECOMMISSIONING nodes status to decide when, after all running containers on
> the node have completed, will be transitioned into DECOMMISSIONED state.
> NodesListManager detect and handle include and exclude list changes to kick
> out decommission or recommission as necessary.
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