Hadoop测试Yarn和MapReduce
1.配置Yarn
（1）配置ResourceManager
生产环境中，一般是重开一台机器作为ResourceManager，这里我们以Master机器代替。
修改yarn-site.xml：
<?xml version="1.0"?>
<!--
Licensed under the Apache License, Version 2.0 (the "License");
you may not use this file except in compliance with the License.
You may obtain a copy of the License at
http://www.apache.org/licenses/LICENSE-2.0
Unless required by applicable law or agreed to in writing, software
distributed under the License is distributed on an "AS IS" BASIS,
WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
See the License for the specific language governing permissions and
limitations under the License. See accompanying LICENSE file.
-->
<configuration>
<property>
<name>yarn.resourcemanager.hostname</name>
<value>master</value>
</property>
<property>
<name>yarn.nodemanager.aux-services</name>
<value>mapreduce_shuffle</value>
</property>
<property>
<name>yarn.nodemanager.auxservices.mapreduce.shuffle.class</name>
<value>org.apache.hadoop.mapred.ShuffleHandler</value>
</property>
<!-- Site specific YARN configuration properties -->
</configuration>
（2）配置NodeManager
NodeManager作为DataNode所在机器的资源管理程序，一般情况下直接放在DataNode所在节点。
修改yarn-site.xml：
<?xml version="1.0"?>
<!--
Licensed under the Apache License, Version 2.0 (the "License");
you may not use this file except in compliance with the License.
You may obtain a copy of the License at
http://www.apache.org/licenses/LICENSE-2.0
Unless required by applicable law or agreed to in writing, software
distributed under the License is distributed on an "AS IS" BASIS,
WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
See the License for the specific language governing permissions and
limitations under the License. See accompanying LICENSE file.
-->
<configuration>
<property>
<name>yarn.resourcemanager.hostname</name>
<value>master</value>
</property>
<property>
<name>yarn.nodemanager.aux-services</name>
<value>mapreduce_shuffle</value>
</property>
<property>
<name>yarn.nodemanager.auxservices.mapreduce.shuffle.class</name>
<value>org.apache.hadoop.mapred.ShuffleHandler</value>
</property>
<!-- Site specific YARN configuration properties -->
</configuration>
（3）启动yarn
在ResourceManager所在机器上：
start-yarn.sh
2.配置MapReduce
copy一份maper-site.xml.template作为maper-site.xml：
<?xml version="1.0"?>
<?xml-stylesheet type="text/xsl" href="configuration.xsl"?>
<!--
Licensed under the Apache License, Version 2.0 (the "License");
you may not use this file except in compliance with the License.
You may obtain a copy of the License at
http://www.apache.org/licenses/LICENSE-2.0
Unless required by applicable law or agreed to in writing, software
distributed under the License is distributed on an "AS IS" BASIS,
WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
See the License for the specific language governing permissions and
limitations under the License. See accompanying LICENSE file.
-->
<!-- Put site-specific property overrides in this file. -->
<configuration>
<property>
<name>mapreduce.framework.name</name>
<value>yarn</value>
</property>
</configuration>
3.测试WordCount实例
（1）上传计算使用文件hello.txt
hello xm
hello sir
java c
python vb
java c++
go php
erlang java
（2）输入测试命令
hadoop jar hadoop/share/hadoop/mapreduce/hadoop-mapreduce-examples-2.7.3.jar wordcount /input/hello.txt /output
（3）查看测试结果
hadoop fs -ls /output
结果：
Found 2 items
-rw-r--r-- 3 root supergroup 0 2018-10-18 15:19 /output/_SUCCESS
-rw-r--r-- 3 root supergroup 70 2018-10-18 15:19 /output/part-r-00000
hadoop fs -text /output/part-r-00000
结果：
c 1
c++ 1
erlang 1
go 1
hello 2
java 3
php 1
python 1
sir 1
vb 1
xm 1