Hadoop集群nodes unhealthy解决方法

在搭建好Hadoop集群之后，所有服务均可正常启动，但是在运行MapReduce程序的时候，发现任务卡在7/09/07 22:28:14 INFO mapreduce.Job: Running job: job_1504781778966_0003，不再往下执行了，经过检查，发现所有的nodes节点都处于unhealthy的状态，使用命令查看node 的状态

bin/yarn node -list -all

查看日志发现

2015-07-16 15:28:58,643 WARN org.apache.hadoop.yarn.server.nodemanager.DirectoryCollection: Directory /opt/beh/data/yarn/nmlocal error, used space above threshold of 90.0%, removing from list of valid directories

2015-07-16 15:28:58,645 WARN org.apache.hadoop.yarn.server.nodemanager.DirectoryCollection: Directory /opt/beh/logs/yarn/nmlogs error, used space above threshold of 90.0%, removing from list of valid directories

2015-07-16 15:28:58,645 INFO org.apache.hadoop.yarn.server.nodemanager.LocalDirsHandlerService: Disk(s) failed: 1/1 local-dirs are bad: /opt/beh/data/yarn/nmlocal; 1/1 log-dirs are bad: /opt/beh/logs/yarn/nmlogs

2015-07-16 15:28:58,645 ERROR org.apache.hadoop.yarn.server.nodemanager.LocalDirsHandlerService: Most of the disks failed. 1/1 local-dirs are bad: /opt/beh/data/yarn/nmlocal; 1/1 log-dirs are bad: /opt/beh/logs/yarn/nmlogs

是node的内存不足导致的！

解决方法 
* 1 把节点上的不用的东西删完，删到90%以下即可 
* 2 在yarn-site.xml中添加以下配置信息，修改上限和下限

  <property>
     <name>yarn.nodemanager.disk-health-checker.min-healthy-disks</name>
     <value>0.0</value>
  </property>
  <property>
     <name>yarn.nodemanager.disk-health-checker.max-disk-utilization-per-disk-percentage</name>
     <value>100.0</value>
 </property>

再重启服务 问题解决。