cd /soft/hadoop/logs/hadoop-centos-zkfc-s101.log发现：
2018-09-29 12:42:03,616 FATAL org.apache.hadoop.ha.ZKFailoverController: Unable to start failover controller. Parent znode does not exist.
Run with -formatZK flag to initialize ZooKeeper.解决方法：zookeeper hadoop-ha znode丢失导致hadoop不能failover的解决办法
High Availability With QJM