注意：要关闭操作系统的防火墙

概述

本文根据官网实现：
https://hadoop.apache.org/docs/r3.0.0/hadoop-project-dist/hadoop-common/SingleCluster.html

修改 mapred-site.xml

vim etc/hadoop/mapred-site.xml

指定MapReduce程序运行在Yarn上，配置如下：

<property>
    <name>mapreduce.framework.name</name>
    <value>yarn</value>
</property>

指定mr运行在yarn上

保存

修改yarn-site.xml

vim etc/hadoop/yarn-site.xml

指定获取数据的方式

<property>
    <name>yarn.nodemanager.aux-services</name>
    <value>mapreduce_shuffle</value>
</property>

不检查虚拟内存

关闭检查内存配置，原因见链接，操作如下：

<property> 
    <name>yarn.nodemanager.vmem-check-enabled</name> 
    <value>false</value> 
</property>

设置classpath

在hadoop3.x中必须设置，否则执行 hadoop-mapreduce-examples-3.0.3.jar 例子报错

执行下面命令，查看classpath：

hadoop classpath

执行结果如下：

/program/hadoop-3.0.3/etc/hadoop:/program/hadoop-3.0.3/share/hadoop/common/lib/*:/program/hadoop-3.0.3/share/hadoop/common/*:/program/hadoop-3.0.3/share/hadoop/hdfs:/program/hadoop-3.0.3/share/hadoop/hdfs/lib/*:/program/hadoop-3.0.3/share/hadoop/hdfs/*:/program/hadoop-3.0.3/share/hadoop/mapreduce/lib/*:/program/hadoop-3.0.3/share/hadoop/mapreduce/*:/program/hadoop-3.0.3/share/hadoop/yarn:/program/hadoop-3.0.3/share/hadoop/yarn/lib/*:/program/hadoop-3.0.3/share/hadoop/yarn/*

在 yarn-site.xml 添加如下：

<property>
    <name>yarn.application.classpath</name>
    <value>/program/hadoop-3.0.3/etc/hadoop:/program/hadoop-3.0.3/share/hadoop/common/lib/*:/program/hadoop-3.0.3/share/hadoop/common/*:/program/hadoop-3.0.3/share/hadoop/hdfs:/program/hadoop-3.0.3/share/hadoop/hdfs/lib/*:/program/hadoop-3.0.3/share/hadoop/hdfs/*:/program/hadoop-3.0.3/share/hadoop/mapreduce/lib/*:/program/hadoop-3.0.3/share/hadoop/mapreduce/*:/program/hadoop-3.0.3/share/hadoop/yarn:/program/hadoop-3.0.3/share/hadoop/yarn/lib/*:/program/hadoop-3.0.3/share/hadoop/yarn/*</value>
</property>

value 部分是 hadoop classpath 执行的结果

保存

启动

start-yarn.sh

web访问

注意：要关闭操作系统的防火墙，否则无法访问

访问：http://hadoop1:8088

停止

stop-yarn.sh

原文出处：/show_1IXYZnvFkzw.html