【Hive】Hive在调用执行MapReduce进程时报错：FAILED: Execution Error, return code 2 from org.apache.hadoop.hive.ql._execution执行器玉mapreduce

今天，在测试Hive时，碰到了以下错误：

hive (default)> INSERT INTO test VALUES ('kuroneko359',20);
Query ID = root_20231207144941_56661aca-5d0c-40c5-83b3-1631434f25a5
Total jobs = 3
Launching Job 1 out of 3
Number of reduce tasks determined at compile time: 1
In order to change the average load for a reducer (in bytes):
  set hive.exec.reducers.bytes.per.reducer=<number>
In order to limit the maximum number of reducers:
  set hive.exec.reducers.max=<number>
In order to set a constant number of reducers:
  set mapreduce.job.reduces=<number>
2023-12-07 14:49:43,919 INFO  [bf528afe-a11e-4444-98a7-aad77cef2125 main] client.RMProxy: Connecting to ResourceManager at bigdata1/192.168.72.101:8032
2023-12-07 14:49:44,095 INFO  [bf528afe-a11e-4444-98a7-aad77cef2125 main] client.RMProxy: Connecting to ResourceManager at bigdata1/192.168.72.101:8032
Starting Job = job_1701931585546_0001, Tracking URL = http://bigdata1:8088/proxy/application_1701931585546_0001/
Kill Command = /opt/module/hadoop/bin/mapred job  -kill job_1701931585546_0001
Hadoop job information for Stage-1: number of mappers: 0; number of reducers: 0
2023-12-07 14:49:50,949 Stage-1 map = 0%,  reduce = 0%
Ended Job = job_1701931585546_0001 with errors
Error during job, obtaining debugging information...
FAILED: Execution Error, return code 2 from org.apache.hadoop.hive.ql.exec.mr.MapRedTask
MapReduce Jobs Launched: 
Stage-Stage-1:  HDFS Read: 0 HDFS Write: 0 FAIL
Total MapReduce CPU Time Spent: 0 msec
hive (default)> 

从报错的内容上看，应该是调用MapReduce时出现了错误。

尽管查看日志，也没有明确的指出出现错误的原因：

于是，我便想到了用Hadoop来执行MapReduce来测试MapReduce的功能是否正常：

hadoop jar $HADOOP_HOME/share/hadoop/mapreduce/hadoop-mapreduce-examples-3.1.3.jar pi 3 10

执行以上命令，发现调用MapReduce时确实出现了问题：

根据程序提供的错误，我们可以得知，是MapReduce找不到Java的位置，导致程序无法正常执行。

解决方法：

在Hadoop的yarn-site.xml中添加JAVA_HOME，添加完之后别忘了分发到其他节点。

再次执行原来的命令，发现又出现了一个新的错误：

解决方法：

在终端中输入：

echo $(hadoop classpath)

获取到hadoop classpath，将结果添加到yarn-site.xml中：

<property>
        <name>yarn.application.classpath</name>
        <value>/opt/module/hadoop/etc/hadoop:/opt/module/hadoop/share/hadoop/common/lib/*:/opt/module/hadoop/share/hadoop/common/*:/opt/module/hadoop/share/hadoop/hdfs:/opt/module/hadoop/share/hadoop/hdfs/lib/*:/opt/module/hadoop/share/hadoop/hdfs/*:/opt/module/hadoop/share/hadoop/mapreduce/lib/*:/opt/module/hadoop/share/hadoop/mapreduce/*:/opt/module/hadoop/share/hadoop/yarn:/opt/module/hadoop/share/hadoop/yarn/lib/*:/opt/module/hadoop/share/hadoop/yarn/*</value>
</property>

保存并分发yarn-site.xml，之后重启yarn。

再次执行先前使用Hadoop运行MapReduce的程序，发现可以正常执行：

之后进入Hive运行刚才的语句，问题成功解决。