详细配置还是得看官网：https://hadoop.apache.org/docs/r3.2.0/hadoop-project-dist/hadoop-common/SingleCluster.html#Pseudo-Distributed_Operation

我配置的是单节点，伪分布式

运行实例wordcount报错

Container exited with a non-zero exit code 1. Error file: prelaunch.err.
Last 4096 bytes of prelaunch.err :
Last 4096 bytes of stderr :
Error: Could not find or load main class org.apache.hadoop.mapreduce.v2.app.MRAppMaster

解决方法：

跟着官网的配置，在etc/hadoop/mapred-site.xml中加入配置

<configuration>
    <property>
        <name>mapreduce.application.classpath</name>
        <value>$HADOOP_MAPRED_HOME/share/hadoop/mapreduce/*:$HADOOP_MAPRED_HOME/share/hadoop/mapreduce/lib/*</value>
    </property>
</configuration>
注意自己的环境变量的配置，就可成功运行
bin/yarn jar share/hadoop/mapreduce/hadoop-mapreduce-examples-3.2.0.jar wordcount /input /output