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A node within a cluster is the location where tasks are run. The tasks are launched with help of a daemon which resides inside the node. This daemon, in the case of Mesos, is Mesos Slave, and in the case of YARN, is NodeManagerNode Manager.

The cgroups Cgroups Linux kernel feature allows aggregating /or partitioning a set of tasks and their future children into hierarchical groups with respect to one or more subsystems. For example: When cgroups , when Cgroups are enabled for the cpu CPU subsystem, and a task is launched by Mesos Slave, it goes under the following hierarchy:

/sys/fs/cgroup/cpu/mesos/<parent-task-id>

During the lifecycle life cycle of this task, if it launches one or more children, they get mounted under the parent task’s hierarchy and can be configured to only use as much resources as the parent task is allowed to:

/sys/fs/cgroup/cpu/mesos/<parent-mesos-id>/hadoop-yarn/<child-yarn-id-1>
/sys/fs/cgroup/cpu/mesos/<parent-mesos-id>/hadoop-yarn/<child-yarn-id-2>

Enabling

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Cgroups for

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meso-slave

To enable

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Cgroups for mesos-slave, start the slave with the following flag:

--isolation=cgroups/cpu,cgroups/mem

Enabling

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Cgroups for YARN

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Node Manager

Enabling Cgroups To enable cgroups for YARN NodeManager involves:

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• Modifying the $YARN_HOME/etc/hadoop/myriad-config-default.yml file.
• Modifying the $YARN_HOME/etc/hadoop/yarn-site.xml file.

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Modify myriad-config-default.yml

Modify the $YARN_HOME/etc/hadoop/myriad-config-default

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.yml file by adding the following content:

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nodemanager:
cgroups: true
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Modify yarn-site.xml

Modify the $YARN_HOME/etc/hadoop/yarn-site.xml file by adding the following content:

<!-- Cgroups configuration -->
<property>
<description>who will execute(launch) the containers.</description>
<name>yarn.nodemanager.container-executor.class</name>
<value>${yarn.nodemanager.container-executor.class}</value>
</property>
<property>
<description>The class which should help the LCE handle resources.</description>
<name>yarn.nodemanager.linux-container-executor.resources-handler.class</name>
<value>${yarn.nodemanager.linux-container-executor.resources-handler.class}</value>
</property>
<property>
<name>yarn.nodemanager.linux-container-executor.cgroups.hierarchy</name>
<value>${yarn.nodemanager.linux-container-executor.cgroups.hierarchy}</value>
</property>
<property>
<name>yarn.nodemanager.linux-container-executor.cgroups.mount</name>
<value>${yarn.nodemanager.linux-container-executor.cgroups.mount}</value>
</property>
<property>
<name>yarn.nodemanager.linux-container-executor.cgroups.mount-path</name>
<value>${yarn.nodemanager.linux-container-executor.cgroups.mount-path}</value>
</property>
<property>
<name>yarn.nodemanager.linux-container-executor.group</name>
<value>${yarn.nodemanager.linux-container-executor.group}</value>
</property>
<property>
<name>yarn.nodemanager.linux-container-executor.path</name>
<value>${yarn.home}/bin/container-executor</value>
</property>

Modify the $YARN_HOME/etc/hadoop/myriad-default-config.yml file by adding the following content:

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nodemanager:
cgroups: true
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