title: Why hbase regionserver keep logging "DISCONNECTING client XXX because read count=-1"?
body: <p>HBase(1.4.9) regionserver keeping logging as follow:</p>
  
  <pre><code>2019-01-30 20:21:50,763 DEBUG [RpcServer.reader=3,bindAddress=xs334,port=16020] ipc.RpcServer: RpcServer.listener,port=16020: DISCONNECTING client 10.34.42.55:13663 because read count=-1. Number of active connections: 78
  2019-01-30 20:21:50,806 DEBUG [RpcServer.listener,port=16020] ipc.RpcServer: RpcServer.listener,port=16020: connection from 10.34.46.58:10661; # active connections: 78
  2019-01-30 20:21:50,822 DEBUG [RpcServer.listener,port=16020] ipc.RpcServer: RpcServer.listener,port=16020: connection from 10.34.42.55:13731; # active connections: 79
  2019-01-30 20:21:50,838 DEBUG [RpcServer.listener,port=16020] ipc.RpcServer: RpcServer.listener,port=16020: connection from 10.34.46.58:10664; # active connections: 80
  2019-01-30 20:21:50,845 DEBUG [RpcServer.reader=0,bindAddress=xs334,port=16020] ipc.RpcServer: RpcServer.listener,port=16020: DISCONNECTING client 10.34.46.56:61446 because read count=-1. Number of active connections: 80
  2019-01-30 20:21:50,848 DEBUG [RpcServer.listener,port=16020] ipc.RpcServer: RpcServer.listener,port=16020: connection from 10.34.46.56:61490; # active connections: 80
  2019-01-30 20:21:50,852 DEBUG [RpcServer.reader=4,bindAddress=xs334,port=16020] ipc.RpcServer: RpcServer.listener,port=16020: DISCONNECTING client 10.34.46.57:18850 because read count=-1. Number of active connections: 80
  2019-01-30 20:21:50,862 DEBUG [RpcServer.reader=5,bindAddress=xs334,port=16020] ipc.RpcServer: RpcServer.listener,port=16020: DISCONNECTING client 10.34.45.55:27506 because read count=-1. Number of active connections: 79
  2019-01-30 20:21:50,865 DEBUG [RpcServer.reader=5,bindAddress=xs334,port=16020] ipc.RpcServer: RpcServer.listener,port=16020: DISCONNECTING client 10.34.46.57:18867 because read count=-1. Number of active connections: 78
  2019-01-30 20:21:50,865 DEBUG [RpcServer.reader=2,bindAddress=xs334,port=16020] ipc.RpcServer: RpcServer.listener,port=16020: DISCONNECTING client 10.34.42.54:54134 because read count=-1. Number of active connections: 77
  2019-01-30 20:21:50,866 DEBUG [RpcServer.reader=1,bindAddress=xs334,port=16020] ipc.RpcServer: RpcServer.listener,port=16020: DISCONNECTING client 10.34.46.56:61448 because read count=-1. Number of active connections: 76
  2019-01-30 20:21:50,871 DEBUG [RpcServer.reader=1,bindAddress=xs334,port=16020] ipc.RpcServer: RpcServer.listener,port=16020: DISCONNECTING client 10.34.46.58:10664 because read count=-1. Number of active connections: 75
  2019-01-30 20:21:50,881 DEBUG [RpcServer.reader=4,bindAddress=xs334,port=16020] ipc.RpcServer: RpcServer.listener,port=16020: DISCONNECTING client 10.34.46.56:61456 because read count=-1. Number of active connections: 74
  2019-01-30 20:21:50,896 DEBUG [RpcServer.reader=8,bindAddress=xs334,port=16020] ipc.RpcServer: RpcServer.listener,port=16020: DISCONNECTING client 10.34.42.44:11076 because read count=-1. Number of active connections: 73
  2019-01-30 20:21:50,897 DEBUG [RpcServer.reader=6,bindAddress=xs334,port=16020] ipc.RpcServer: RpcServer.listener,port=16020: DISCONNECTING client 10.34.46.60:29865 because read count=-1. Number of active connections: 72
  2019-01-30 20:21:50,905 DEBUG [RpcServer.reader=7,bindAddress=xs334,port=16020] ipc.RpcServer: RpcServer.listener,port=16020: DISCONNECTING client 10.34.46.57:18925 because read count=-1. Number of active connections: 71
  2019-01-30 20:21:50,908 DEBUG [RpcServer.listener,port=16020] ipc.RpcServer: RpcServer.listener,port=16020: connection from 10.34.46.59:13601; # active connections: 71
  2019-01-30 20:21:50,915 DEBUG [RpcServer.reader=9,bindAddress=xs334,port=16020] ipc.RpcServer: RpcServer.listener,port=16020: DISCONNECTING client 10.34.46.59:13537 because read count=-1. Number of active connections: 71
  2019-01-30 20:21:50,923 DEBUG [RpcServer.reader=8,bindAddress=xs334,port=16020] ipc.RpcServer: RpcServer.listener,port=16020: DISCONNECTING client 10.34.42.54:54124 because read count=-1. Number of active connections: 70
  2019-01-30 20:21:50,931 DEBUG [RpcServer.reader=6,bindAddress=xs334,port=16020] ipc.RpcServer: RpcServer.listener,port=16020: DISCONNECTING client 10.34.42.44:11047 because read count=-1. Number of active connections: 69
  2019-01-30 20:21:50,932 DEBUG [RpcServer.reader=1,bindAddress=xs334,port=16020] ipc.RpcServer: RpcServer.listener,port=16020: DISCONNECTING client 10.34.42.43:53576 because read count=-1. Number of active connections: 68
  2019-01-30 20:21:50,949 DEBUG [RpcServer.reader=7,bindAddress=xs334,port=16020] ipc.RpcServer: RpcServer.listener,port=16020: DISCONNECTING client 10.34.46.57:18873 because read count=-1. Number of active connections: 67
  2019-01-30 20:21:50,949 DEBUG [RpcServer.reader=0,bindAddress=xs334,port=16020] ipc.RpcServer: RpcServer.listener,port=16020: DISCONNECTING client 10.34.42.44:11074 because read count=-1. Number of active connections: 66
  2019-01-30 20:21:51,003 DEBUG [RpcServer.listener,port=16020] ipc.RpcServer: RpcServer.listener,port=16020: connection from 10.34.46.56:61540; # active connections: 66
  2019-01-30 20:21:51,011 DEBUG [RpcServer.listener,port=16020] ipc.RpcServer: RpcServer.listener,port=16020: connection from 10.34.46.56:61547; # active connections: 67
  2019-01-30 20:21:51,013 DEBUG [RpcServer.listener,port=16020] ipc.RpcServer: RpcServer.listener,port=16020: connection from 10.34.45.55:27540; # active connections: 68
  </code></pre>
  
  <p>I found similar question here <a href="https://stackoverflow.com/questions/34543204/exceptions-in-hbase-region-server">Exceptions in Hbase Region Server</a>, however it doesn't seems right for my config is </p>
  
  <pre><code>  &lt;property&gt;
      &lt;name&gt;hbase.zookeeper.property.maxClientCnxns&lt;/name&gt;
      &lt;value&gt;300&lt;/value&gt;
      &lt;description&gt;Property from ZooKeeper's config zoo.cfg.
      Limit on number of concurrent connections (at the socket level) that a
      single client, identified by IP address, may make to a single member of
      the ZooKeeper ensemble. Set high to avoid zk connection issues running
      standalone and pseudo-distributed.&lt;/description&gt;
    &lt;/property&gt;
  </code></pre>
  
  <p>I also found that the ip above was from other regionservers. Is that normal? Why this happend?</p>