概要描述

一个Kafka集群中同时只会有一个Controller，可以在TDH客户端的ZooKeeper中查询当前Controller所在节点。

详细说明

可以进入ZooKeeper客户端后，查看Kafka集群当前Controller节点。

1. 参照如下KB准备TDH客户端（TDH Client）环境：
   https://nj.transwarp.cn:8180/?p=1105
2. 进入TDH-Client/zookeeper/bin目录，运行 zookeeper-client 登录ZooKeeper CLI:

   [root@bryan1 bin]# pwd
   /home/Bryan/TDH-Client/zookeeper/bin
   [root@bryan1 bin]# ./zookeeper-client
   Connecting to localhost:2181
   log4j:WARN No appenders could be found for logger (org.apache.zookeeper.ZooKeeper).
   log4j:WARN Please initialize the log4j system properly.
   Welcome to ZooKeeper!
   JLine support is enabled
   　
   WATCHER::
   　
   WatchedEvent state:SyncConnected type:None path:null
   [zk: localhost:2181(CONNECTED) 0]

3. 在ZooKeeper CLI界面下，输入 get /controller 命令获取当前Controller信息：

   [zk: localhost:2181(CONNECTED) 2] get /controller
   {"version":1,"brokerid":5,"timestamp":"1548580409165"}
   cZxid = 0x4000001b2
   ctime = Sun Jan 27 17:13:29 CST 2019
   mZxid = 0x4000001b2
   mtime = Sun Jan 27 17:13:29 CST 2019
   pZxid = 0x4000001b2
   cversion = 0
   dataVersion = 0
   aclVersion = 0
   ephemeralOwner = 0xd688e93b26f0038
   dataLength = 54
   numChildren = 0
   //关键字："brokerid":5表示Broker ID为5

4. 根据第3步获取到的Broker ID信息，输入命令 get /brokers/ids/ID值 获得对应Controller节点的信息：

   [zk: localhost:2181(CONNECTED) 8] get /brokers/ids/5
   {"listener_security_protocol_map":{"PLAINTEXT":"PLAINTEXT"},"endpoints":["PLAINTEXT://tdh500-174:9092"],"jmx_port":9999,"host":"t......
   //关键字["PLAINTEXT://tdh500-174:9092"]，表示tdh500-174即为当前Controller节点。

   如上所示，tdh500-174就是当前Controller节点。