INFO Closed socket connection for client /127.0.0.1:48452 which had sessionid 0x15698f5ac360001 (org.apache.zookeeper.server.NIOServerCnxn)

Question

I installed fresh zookeeper & kafka both. I started them both. Then when I want to see the list of topics with this command:

bin/kafka-topics.sh --list --zookeeper localhost 2181

It gives me the socket connection closed. Here is the screen shot:

    darpanshah@darpan-ubuntu:/opt/Kafka$ bin/kafka-topics.sh --list --zookeeper localhost 2181 
2016-08-17 10:44:44,053] INFO Accepted socket connection from /127.0.0.1:48452 (org.apache.zookeeper.server.NIOServerCnxnFactory)
    [2016-08-17 10:44:44,059] INFO Client attempting to establish new session at /127.0.0.1:48452 (org.apache.zookeeper.server.ZooKeeperServer)
    [2016-08-17 10:44:44,069] INFO Established session 0x15698f5ac360001 with negotiated timeout 30000 for client /127.0.0.1:48452 (org.apache.zookeeper.server.ZooKeeperServer)
    [2016-08-17 10:44:44,095] INFO Processed session termination for sessionid: 0x15698f5ac360001 (org.apache.zookeeper.server.PrepRequestProcessor)
    [2016-08-17 10:44:44,105] INFO Closed socket connection for client /127.0.0.1:48452 which had sessionid 0x15698f5ac360001 (org.apache.zookeeper.server.NIOServerCnxn)
    darpanshah@darpan-ubuntu:/opt/Kafka$

Thanks in advance. Got stuck.

Answer 1

That is not an error. The topic details are fetched from Zookeeper. Hence the client (invoked by kafka-topics.sh) first connects to Zookeeper, then establishes a session, gets the data and then disconnects at the end. This is the expected behavior of any clients that will get some data from Zookeeper.