Error: Could not find or load main class org.apache.hadoop.mapred.YarnChild

1. 執行hadoop classpath
2. 在hadoop配置文件 yarn-site中添加以下配置 <property> <name>yarn.application.classpath</name>
           <value>/home/hadoop/hadoop-3.3.1/etc/hadoop:/home/hadoop/hadoop-3.3.1/share/hadoop/common/lib/:/home/hadoop/hadoop-3.3.1/share/hadoop/common/:/home/hadoop/hadoop-3.3.1/share/hadoop/hdfs:/home/hadoop/hadoop-3.3.1/share/hadoop/hdfs/lib/:/home/hadoop/hadoop-3.3.1/share/hadoop/hdfs/:/home/hadoop/hadoop-3.3.1/share/hadoop/mapreduce/:/home/hadoop/hadoop-3.3.1/share/hadoop/yarn:/home/hadoop/hadoop-3.3.1/share/hadoop/yarn/lib/:/home/hadoop/hadoop-3.3.1/share/hadoop/yarn/*</value>
       </property>
3. 執行 source /etc/profile
4. 重啟生效