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https://issues.apache.org/jira/browse/YARN-8031?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16402162#comment-16402162
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Miklos Szegedi commented on YARN-8031:
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[~jayceAu], thank you for raising this. If you have CGroups already mounted,
you should set the mount option to false as described here:
[https://hadoop.apache.org/docs/current/hadoop-yarn/hadoop-yarn-site/NodeManagerCgroups.html]
{code:java}
Discover CGroups mounted already This should be used on newer systems
like RHEL7 or Ubuntu16 or if the administrator mounts CGroups before YARN
starts. Set yarn.nodemanager.linux-container-executor.cgroups.mount to false
and leave other settings set to their defaults. YARN will locate the mount
points in /proc/mounts. Common locations include /sys/fs/cgroup and /cgroup.
The default location can vary depending on the Linux distribution in use.{code}
> NodeManager will fail to start if cpu subsystem is already mounted
> ------------------------------------------------------------------
>
> Key: YARN-8031
> URL: https://issues.apache.org/jira/browse/YARN-8031
> Project: Hadoop YARN
> Issue Type: Bug
> Components: nodemanager
> Affects Versions: 2.5.0
> Reporter: JayceAu
> Priority: Major
> Attachments: image-2018-03-15-14-47-30-583.png
>
>
> if *yarn.nodemanager.linux-container-executor.cgroups.mount* is set to true
> and cpu subsystem is not yet mounted, NodeManager will mount the cpu
> subsystem and then create the control group whose default name is
> *hadoop-yarn* if the mount step is successful. This procedure works well if
> cpu subsystem is not yet mounted. However, under some situation cpu subsystem
> is already mounted before NodeManager starts and NodeManager will fail to
> start because of no write permission to the *hadoop-yarn* path . For example:
> # in OS that use systemd such as centos7 will have cpu subsystem mounted by
> default on machine startup
> # some deamon whose start order is more precedent than NodeManager may also
> rely on the mounted state of cpu subsystem. In our production environment, we
> limit the cpu usage of the monitoring and control agent, which starts on
> reboot
> In order to solve this problem, container-executor must be able to create the
> control group *hadoop-yarn* if mounting controller is successful or this
> controller is already mounted. Besides, if cpu subsystem is used in
> combination with other subsystem and it's already mounted, container-executor
> should use the latest mount point of cpu subsystem instread of the one
> provided by NodeManager.
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