Hi Jerry,   Thank you for your reply.   But when the zookeeper thorws "Unexpected exception causing shutdown while sock still open" (Maybe because of the Internet),  kafka shoud reconnect zookeeper, kafka log :   2018-11-28 10:07:13,920 INFO org.apache.zookeeper.ClientCnxn: Unable to read additional data from server sessionid 0x36666f33c21940c, likely server has closed socket, closing socket connection and attempting reconnect 2018-11-28 10:07:14,021 INFO org.I0Itec.zkclient.ZkClient: zookeeper state changed (Disconnected) 2018-11-28 10:07:14,874 INFO org.apache.zookeeper.ClientCnxn: Opening socket connection to server ylxny-uat-cdh2/10.8.100.77:2181. Will not attempt to authenticate using SASL (unknown error) 2018-11-28 10:07:14,875 INFO org.apache.zookeeper.ClientCnxn: Socket connection established, initiating session, client: /10.8.100.82:48766, server: ylxny-uat-cdh2/10.8.100.77:2181 2018-11-28 10:07:14,877 INFO org.I0Itec.zkclient.ZkClient: zookeeper state changed (Expired) 2018-11-28 10:07:14,877 INFO org.apache.zookeeper.ClientCnxn: Unable to reconnect to ZooKeeper service, session 0x36666f33c21940c has expired, closing socket connection 2018-11-28 10:07:14,877 INFO org.apache.zookeeper.ZooKeeper: Initiating client connection, connectString=ylxny-uat-cdh2:2181,ylxny-uat-cdh3:2181,ylxny-uat-cdh4:2181,ylxny-uat-cdh5:2181,ylxny-uat-cdh6:2181 sessionTimeout=6000 watcher=org.I0Itec.zkclient.ZkClient@40bffbca 2018-11-28 10:07:14,878 INFO org.apache.zookeeper.ClientCnxn: EventThread shut down 2018-11-28 10:07:14,881 INFO org.apache.zookeeper.ClientCnxn: Opening socket connection to server ylxny-uat-cdh5/10.8.100.80:2181. Will not attempt to authenticate using SASL (unknown error) 2018-11-28 10:07:14,883 INFO org.apache.zookeeper.ClientCnxn: Socket connection established, initiating session, client: /10.8.100.82:49360, server: ylxny-uat-cdh5/10.8.100.80:2181 2018-11-28 10:07:14,890 INFO org.apache.zookeeper.ClientCnxn: Session establishment complete on server ylxny-uat-cdh5/10.8.100.80:2181, sessionid = 0x467581202b00000, negotiated timeout = 6000 2018-11-28 10:07:14,890 INFO org.I0Itec.zkclient.ZkClient: zookeeper state changed (SyncConnected) 2018-11-28 10:07:14,890 INFO kafka.server.KafkaHealthcheck$SessionExpireListener: re-registering broker info in ZK for broker 62   Why kafka thorws "A broker is already registered on the path /brokers/ids/62" ? At this time kafka broker status is bad.    I think it might be a kafka or zookeeper bug.   CDH version: 5.13.1-1.cdh5.13.1.p0.2 Kafka version: 3.1.0-1.3.1.0.p0.35   ... View more