YARN的队列配置
YARN默认采用的调度器是容量调度，且默认只有一个任务队列。该调度器内单个队列的调度策略为FIFO，因此在单个队列中的任务并行度为1。那么就会出现单个任务阻塞的情况，如果随着业务的增长，充分的利用到集群的使用率，我们就需要手动的配置多条任务队列。
配置任务队列
默认YARN只有一个default任务队列，现在我们添加一个small的任务队列。
修改配置文件: $HADOOP_HOME/etc/hadoop/capacity-scheduler.xml
<configuration>
<!-- 不需要修改 -->
<!-- 容量调度器中最多容纳多少个Job -->
<property>
<name>yarn.scheduler.capacity.maximum-applications</name>
<value>10000</value>
<description>
Maximum number of applications that can be pending and running.
</description>
</property>
<!-- 不需要修改 -->
<!-- MRAppMaster进程所占的资源可以占用队列总资源的百分比，可以通过修改这个参数来限制队列中提交Job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>
<!-- 不需要修改 -->
<!-- 为Job分配资源的时候，使用什么策略 -->
<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>
<!-- 修改!!! -->
<!-- 调度器中有什么队列，我们添加一个small队列 -->
<property>
<name>yarn.scheduler.capacity.root.queues</name>
<value>default,small</value>
<description>
The queues at the this level (root is the root queue).
</description>
</property>
<!-- 修改!!! -->
<!-- 配置default队列的容量百分比 -->
<property>
<name>yarn.scheduler.capacity.root.default.capacity</name>
<value>70</value>
<description>Default queue target capacity.</description>
</property>
<!-- 新增!!! -->
<!-- 新增small队列的容量百分比 -->
<!-- 所有的队列容量百分比和需要是100 -->
<property>
<name>yarn.scheduler.capacity.root.small.capacity</name>
<value>30</value>
<description>Default queue target capacity.</description>
</property>
<!-- 不需要修改 -->
<!-- default队列用户能使用的容量最大百分比 -->
<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>
<!-- 添加!!! -->
<!-- small队列用户能使用的容量最大百分比 -->
<property>
<name>yarn.scheduler.capacity.root.small.user-limit-factor</name>
<value>1</value>
<description>
Default queue user limit a percentage from 0.0 to 1.0.
</description>
</property>
<!-- 不需要修改 -->
<!-- default队列能使用的容量最大百分比 -->
<property>
<name>yarn.scheduler.capacity.root.default.maximum-capacity</name>
<value>100</value>
<description>
The maximum capacity of the default queue.
</description>
</property>
<!-- 添加!!! -->
<!-- small队列能使用的容量最大百分比 -->
<property>
<name>yarn.scheduler.capacity.root.small.maximum-capacity</name>
<value>100</value>
<description>
The maximum capacity of the default queue.
</description>
</property>
<!-- 不需要修改 -->
<!-- default队列的状态 -->
<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>
<!-- 添加!!! -->
<!-- small队列的状态 -->
<property>
<name>yarn.scheduler.capacity.root.small.state</name>
<value>RUNNING</value>
<description>
The state of the default queue. State can be one of RUNNING or STOPPED.
</description>
</property>
<!-- 不需要修改 -->
<!-- 限制向队列提交的用户-->
<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>
<!-- 添加!!! -->
<property>
<name>yarn.scheduler.capacity.root.small.acl_submit_applications</name>
<value>*</value>
<description>
The ACL of who can submit jobs to the default queue.
</description>
</property>
<!-- 不需要修改 -->
<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>
<!-- 添加!!! -->
<property>
<name>yarn.scheduler.capacity.root.small.acl_administer_queue</name>
<value>*</value>
<description>
The ACL of who can administer jobs on the default queue.
</description>
</property>
<!-- 不需要修改 -->
<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>
<!-- 不需要修改 -->
<property>
<name>yarn.scheduler.capacity.queue-mappings</name>
<value></value>
<description>
A list of mappings that will be used to assign jobs to queues
The syntax for this list is [u|g]:[name]:[queue_name][,next mapping]*
Typically this list will be used to map users to queues,
for example, u:%user:%user maps all users to queues with the same name
as the user.
</description>
</property>
<!-- 不需要修改 -->
<property>
<name>yarn.scheduler.capacity.queue-mappings-override.enable</name>
<value>false</value>
<description>
If a queue mapping is present, will it override the value specified
by the user? This can be used by administrators to place jobs in queues
that are different than the one specified by the user.
The default is false.
</description>
</property>
</configuration>分发配置到各个节点
[root@qianfeng01 ~]# cd $HADOOP_HOME/etc/hadoop
[root@qianfeng01 hadoop]# scp capacity-scheduler.xml qianfeng02:$PWD
[root@qianfeng01 hadoop]# scp capacity-scheduler.xml qianfeng03:$PWD
# 重启集群
[root@qianfeng01 hadoop]# stop-yarn.sh
[root@qianfeng01 hadoop]# start-yarn.sh提交任务
# 提交Job到default队列，其中的-Dmapreduce.job.queuename可以不指定，因为现在默认向default队列提交Job
[root@qianfeng01 ~]# hadoop jar $HADOOP_HOME/share/hadoop/mapreduce/hadoop-mapreduce-examples-3.3.1.jar wordcount -Dmapreduce.job.queuename=default /input /output1
# 提交Job到small队列
[root@qianfeng01 ~]# hadoop jar $HADOOP_HOME/share/hadoop/mapreduce/hadoop-mapreduce-examples-3.3.1.jar wordcount -Dmapreduce.job.queuename=small /input /output2查看任务
默认队列设置
YARN默认将任务提交到default队列，我们如果需要提交到其他的队列中，可以使用-Dmapreduce.job.queuename指定提交的队列。也可以设置默认的任务提交队列。
例如: Hive的底层会把HQL语句翻译成MapReduce的程序执行，我们可以创建一个hive队列，将这个队列的容量设置的大一些。我们可以设置默认将任务提交到这个队列中。如果需要往其他的队列中提交任务的话，可以再使用-Dmapreduce.job.queuename去提交了。
<!--配置默认的提交队列-->
<property>
<name>mapreduce.job.queuename</name>
<value>small</value>
</property>
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