title: WARN Session 0x0 for server null, unexpected error, closing socket connection and attempting reconnect
body: <p>I have two nodes that each one has docker with Mesos,marathon,and zookeeper have been installed on it. This is my docker compose file on master node:</p>
  
  <pre><code>version: '3.7'
   services:
    zookeeper:
     image: ubuntu_mesos_home_marzieh
     command: /home/zookeeper-3.4.8/bin/zkServer.sh restart
    environment:
      ZOOKEEPER_SERVER_ID: 1
      ZOOKEEPER_CLIENT_PORT: 2190
      ZOOKEEPER_TICK_TIME: 2000
      ZOOKEEPER_INIT_LIMIT: 10
      ZOOKEEPER_SYNC_LIMIT: 5
      ZOOKEEPER_SERVERS: 150.20.11.133:2888:3888;150.20.11.136:2888:3888
    network_mode: host
    expose:
      - 2190
      - 2888
      - 3888
    ports:
      - 2190:2190
      - 2888:2888
      - 3888:3888
  
   master-mesos:
    image: ubuntu_mesos_home_marzieh
    command: bash -c "sleep 30; /home/mesos-1.7.0/build/bin/mesos- 
      master.sh --ip=150.20.11.133 --work_dir=/var/run/mesos 
      --hostname=150.20.11.133" 
    privileged: true
    restart: always
    network_mode: host
    depends_on:
      - zookeeper
    environment:
      - LIBPROCESS_IP=150.20.11.133
      - MESOS_HOSTNAME="150.20.11.133"
      - MESOS_QUORUM=1
      - MESOS_LOG_DIR=/var/log/mesos
      - MESOS_WORK_DIR=/var/run/mesos
    expose:
      - 5050
      - 4040
      - 7077
      - 8080
    ports:
      - 5050:5050
      - 4040:4040
      - 7077:7077
      - 8080:8080
  
   marathon:
    image: ubuntu_mesos_home_marzieh
    command: bash -c "sleep 60; /usr/share/marathon/bin/marathon"
    privileged: true
    network_mode: host
    depends_on:
      - zookeeper
      - master-mesos
    environment:
      - HOSTNAME="150.20.11.133"
      - MARATHON_ZK=zk://150.20.11.133:2190/marathon
      - MARATHON_MASTER=zk://150.20.11.133:2190/mesos
      - MESOS_NATIVE_JAVA_LIBRARY=/usr/local/lib/libmesos.so
      - MARATHON_HTTP_PORT=8080
    expose:
      - 8080
      - 2190
    ports:
      - 8080:8080
      - 2190:2190
  </code></pre>
  
  <p>This is docker compose for slave node:</p>
  
  <pre><code> version: '3.7'
    services:
     zookeeper:
       image: ubuntu_mesos_home_marzieh
       command: /home/zookeeper-3.4.8/bin/zkServer.sh start
       environment:
         ZOOKEEPER_SERVER_ID: 2
         ZOOKEEPER_CLIENT_PORT: 2190
         ZOOKEEPER_TICK_TIME: 2000
         ZOOKEEPER_INIT_LIMIT: 10
         ZOOKEEPER_SYNC_LIMIT: 5
         ZOOKEEPER_SERVERS: 
         150.20.11.133:2888:3888;150.20.11.136:2888:3888
      network_mode: host
      expose:
       - 2190
       - 2888
       - 3888
      ports:
       - 2190:2190
       - 2888:2888
       - 3888:3888
  
    slave-mesos:
       image: ubuntu_mesos_home_marzieh
       command: bash -c "sleep 40; /home/mesos-1.7.0/build/bin/mesos- 
       slave.sh --master=150.20.11.133:5050 --work_dir=/var/run/mesos
       --systemd_enable_support=false"
       privileged: true
       restart: always
       privileged: true
       network_mode: host
       depends_on:
        - zookeeper
       environment:
         - MESOS_RESOURCES=ports(*):[11000-11999]
         - LIBPROCESS_IP=150.20.11.136
         - MESOS_HOSTNAME="150.20.11.136"
         - MESOS_EXECUTOR_REGISTRATION_TIMEOUT=5mins 
         - MESOS_LOG_DIR=/var/log/mesos
         - MESOS_WORK_DIR=/var/run/mesos
         - MESOS_LOGGING_LEVEL=INFO
       expose:
         - 5051
       ports:
         - 5051:5051
  
     marathon:
      image: ubuntu_mesos_home_marzieh
      command: bash -c "sleep 60; /usr/share/marathon/bin/marathon"
      privileged: true
      network_mode: host
      depends_on:
        - zookeeper
        - slave-mesos
      environment:
        - MARATHON_ZK=zk://150.20.11.133:2190/marathon
        - MARATHON_MASTER=zk://150.20.11.133:2190/mesos
        - MESOS_NATIVE_JAVA_LIBRARY=/usr/local/lib/libmesos.so
        - MARATHON_HTTP_PORT=8080
      expose:
        - 8080
        - 2190
      ports:
        - 8080:8080
        - 2190:2190
  </code></pre>
  
  <p>I configured Zookeeper on "zoo.cfg" and made "myid" file for every node. Also I configured Mesos and Marathon. But when I ran docker compose on master node (150.20.11.133), I got this error:</p>
  
  <blockquote>
    <p>marathon_1      | java.net.ConnectException: Connection refused
    marathon_1      |   at sun.nio.ch.SocketChannelImpl.checkConnect(Native Method)</p>
    
    <p>marathon_1      |  at sun.nio.ch.SocketChannelImpl.finishConnect(SocketChannelImpl.java:717)
    marathon_1      |   at org.apache.zookeeper.ClientCnxnSocketNIO.doTransport(ClientCnxnSocketNIO.java:361)</p>
    
    <p>marathon_1      |  at org.apache.zookeeper.ClientCnxn$SendThread.run(ClientCnxn.java:1144)
    marathon_1      | [2019-02-16 13:38:14,087] INFO  Opening socket connection to server 172.28.10.133/172.28.10.133:2190. Will not attempt to authenticate using SASL (unknown error) (org.apache.zookeeper.ClientCnxn:main-SendThread(172.28.10.133:2190))</p>
    
    <p>marathon_1      | [2019-02-16 13:38:14,087] WARN  Session 0x0 for server null, unexpected error, closing socket connection and attempting reconnect (org.apache.zookeeper.ClientCnxn:main-SendThread(172.28.10.133:2190))</p>
    
    <p>marathon_1      | java.net.ConnectException: Connection refused
    marathon_1      |   at sun.nio.ch.SocketChannelImpl.checkConnect(Native Method)</p>
    
    <p>marathon_1      |  at sun.nio.ch.SocketChannelImpl.finishConnect(SocketChannelImpl.java:717)</p>
    
    <p>marathon_1      |  at org.apache.zookeeper.ClientCnxnSocketNIO.doTransport(ClientCnxnSocketNIO.java:361)</p>
    
    <p>marathon_1      |  at org.apache.zookeeper.ClientCnxn$SendThread.run(ClientCnxn.java:1144)
    marathon_1      | [2019-02-16 13:38:14,173] ERROR Failed to connect to ZK. Marathon will exit now. (mesosphere.marathon.core.storage.store.impl.zk.RichCuratorFramework:main)</p>
  </blockquote>
  
  <p>I don't know what happen. I tried to open every port with <strong>ufw</strong> or I disabled firewall, but error did not go away. Would you please tell me what is wrong with docker compose file? </p>
  
  <p>Any help would be appreciated. </p>
  
  <p>Thanks.</p>