<configuration>

  <property>
　　 <!--集群中允许运行和排队的最大的应用程序数量,如果如果提交的任务超过这个数量的话，那么多余的任务将不会被MR接受-->

    <name>yarn.scheduler.capacity.maximum-applications</name>

    <value>10000</value>

    <description>

      Maximum number of applications that can be pending and running.

    </description>

  </property>


  <!--集群中允许运行ApplicationMater的资源百分比，控制并发运行应用程序的数量-->

  <property>

    <name>yarn.scheduler.capacity.maximum-am-resource-percent</name>

    <value>0.1</value>

    <description>

      Maximum percent of resources in the cluster which can be used to run

      application masters i.e. controls number of concurrent running

      applications.

    </description>

  </property>


　<!--将用于比较调度程序中的资源的ResourceCalculator实现，默认是在只使用内存的时候进行资源比较-->

  <property>

    <name>yarn.scheduler.capacity.resource-calculator</name>

    <value>org.apache.hadoop.yarn.util.resource.DefaultResourceCalculator</value>

    <description>

      The ResourceCalculator implementation to be used to compare

      Resources in the scheduler.

      The default i.e. DefaultResourceCalculator only uses Memory while

      DominantResourceCalculator uses dominant-resource to compare

      multi-dimensional resources such as Memory, CPU etc.

    </description>

  </property>


　<!--指定root下的所有的队列，用逗号进行分割-->

  <property>

    <name>yarn.scheduler.capacity.root.queues</name>

    <value>default</value>

    <description>

      The queues at the this level (root is the root queue).

    </description>

  </property>
　　
　<!--指定default下的所有队列，依次类推-->
  <property>
　　 <name>yarn.scheduler.capacity.root.user1.queues</name>
　　 <value>usera,userb,userc</value>
　</property>


  <!--指定默认default用户使用的资源百分比，因为这里root下只有default一个用户，所以使用了全部的资源-->

  <property>

    <name>yarn.scheduler.capacity.root.default.capacity</name>

    <value>100</value>

    <description>Default queue target capacity.</description>

  </property>


　<!--限制default下的具体的每个用户可以使用的最多的资源百分比，用小数表示，1说明是百分百-->

  <property>

    <name>yarn.scheduler.capacity.root.default.user-limit-factor</name>

    <value>1</value>

    <description>

      Default queue user limit a percentage from 0.0 to 1.0.

    </description>

  </property>


　<!--限制default用户最多可以得到集群总资源的百分比,这里只有一个用户，所以为百分百-->

  <property>

    <name>yarn.scheduler.capacity.root.default.maximum-capacity</name>

    <value>100</value>

    <description>

      The maximum capacity of the default queue.

    </description>

  </property>


　<!--队列状态：如果一个队列的状态是STOPPED，则不能向其提交应用程序或子队列提交应用程序-->

  <property>

    <name>yarn.scheduler.capacity.root.default.state</name>

    <value>RUNNING</value>

    <description>

      The state of the default queue. State can be one of RUNNING or STOPPED.

    </description>

  </property>


  <!--限定那些用户或者是用户组可以给给定的队列提交应用程序-->

  <property>

    <name>yarn.scheduler.capacity.root.default.acl_submit_applications</name>
　　 <value>*</value>

    <description>  
　　　　The ACL of who can submit jobs to the default queue.

    </description>

  </property>

  <property>

    <name>yarn.scheduler.capacity.root.default.acl_administer_queue</name>

    <value>*</value>

    <description>

      The ACL of who can administer jobs on the default queue.

    </description>

  </property>

  <property>

    <name>yarn.scheduler.capacity.node-locality-delay</name>

    <value>40</value>

    <description>

      Number of missed scheduling opportunities after which the CapacityScheduler

      attempts to schedule rack-local containers.

      Typically this should be set to number of nodes in the cluster, By default is setting

      approximately number of nodes in one rack which is 40.

    </description>

  </property>

</configuration>