【Hadoop】集群运行卡在Kill Command = /opt/module/hadoop-2.7.2/bin/hadoop job -kill job

当hive运行卡主不动时，报错如下

hive (default)> select count(*) cnt from emp;

Query ID = root_20200220175612_bb456a03-2298-4d20-82b9-c0a96ae859a0
Total jobs = 1
Launching Job 1 out of 1
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=
In order to limit the maximum number of reducers:
  set hive.exec.reducers.max=
In order to set a constant number of reducers:
  set mapreduce.job.reduces=
Starting Job = job_1582192539192_0001, Tracking URL = http://hadoop103:8088/proxy/application_1582192539192_0001/
Kill Command = /opt/module/hadoop-2.7.2/bin/hadoop job  -kill job_1582192539192_0001

原因：hive程序在运行是其实就是转换成MapReduce来运行的，可能在搭建的时候将运行内存设置的过于小了，我们可以将运行内存设置成如下即可。
打开hadoop安装文件下的yarn-site.xml文件

  
    yarn.nodemanager.aux-services
    mapreduce_shuffle
  
  
    yarn.nodemanager.aux-services.mapreduce_shuffle.class
    org.apache.hadoop.mapred.ShuffleHandler
  

如果在运行MapReduce时也发生上述情况的话，也可以使用同样的方法来进行操作