1. 在ZooKeeper ensemble中怎么查找Leader
   这里提供两种方法
   一种是在每个node上执行下面的命令看看哪个node是下面的输出
   

   # grep LEAD /var/log/zookeeper/zookeeper-zookeeper-server-xyz.out
   2016-02-29 22:33:47,113 - INFO  [QuorumPeer[myid=3]/0:0:0:0:0:0:0:0:2181:QuorumPeer@829] - LEADING
   2016-02-29 22:33:47,114 - INFO  [QuorumPeer[myid=3]/0:0:0:0:0:0:0:0:2181:Leader@358] - LEADING - LEADER ELECTION TOOK - 9066

   另一种方法是在每个node上使用nc命令

   # echo stat | nc localhost 2181 | grep Mode
   Mode: leader
   
   # echo stat | nc localhost 2181 | grep Mode
   Mode: follower

    

ZooKeeper常用命令