之前一直好好的，三个虚拟机，现在两个都启动不起来，第一次启动的时候还会有QuorumPeerMain进程，但基本上三秒就自动关闭了，之后再启动就启动不起来了，连这个进程也不会出现了。重装也试过了，还是一样。
出问题的是master和slave01节点，slave02正常。打开hadoop的时候，slave01也无法正常启动。
dataLogDir=/usr/zookeeper/var/datalog
但是我把之前的日志都清空之后，再启动也没有新的日志产生
zookeeper的日志怎么查看？
2016-12-21 20:01:13,571 INFO org.apache.hadoop.hdfs.server.datanode.DataNode: registered UNIX signal handlers for [TERM, HUP, INT]
2016-12-21 20:01:15,464 WARN org.apache.hadoop.util.NativeCodeLoader: Unable to load native-hadoop library for your platform... using builtin-java classes where applicable
2016-12-21 20:01:15,977 FATAL org.apache.hadoop.hdfs.server.datanode.DataNode: Exception in secureMain
java.net.UnknownHostException: slave01: slave01
at java.net.InetAddress.getLocalHost(InetAddress.java:1473)
at org.apache.hadoop.security.SecurityUtil.getLocalHostName(SecurityUtil.java:187)
at org.apache.hadoop.security.SecurityUtil.login(SecurityUtil.java:207)
at org.apache.hadoop.hdfs.server.datanode.DataNode.instantiateDataNode(DataNode.java:2213)
at org.apache.hadoop.hdfs.server.datanode.DataNode.createDataNode(DataNode.java:2262)
at org.apache.hadoop.hdfs.server.datanode.DataNode.secureMain(DataNode.java:2438)
at org.apache.hadoop.hdfs.server.datanode.DataNode.main(DataNode.java:2462)
Caused by: java.net.UnknownHostException: slave01
at java.net.Inet4AddressImpl.lookupAllHostAddr(Native Method)
at java.net.InetAddress$1.lookupAllHostAddr(InetAddress.java:901)
at java.net.InetAddress.getAddressesFromNameService(InetAddress.java:1293)
at java.net.InetAddress.getLocalHost(InetAddress.java:1469)
... 6 more
2016-12-21 20:01:15,980 INFO org.apache.hadoop.util.ExitUtil: Exiting with status 1
2016-12-21 20:01:16,011 INFO org.apache.hadoop.hdfs.server.datanode.DataNode: SHUTDOWN_MSG:
/************************************************************
SHUTDOWN_MSG: Shutting down DataNode at java.net.UnknownHostException: slave01: slave01
************************************************************/
这是hadoop的异常报告，也是slave01连上之后就掉
但是互相之间ping通没问题，ssh连接也没问题