title: ZooKepper Unable to start AdminServer, exiting abnormally
body: <p>I'm using apache-zookeeper-3.5.5 and I want to run zkServer but I get the below error:</p>
  
  <p>When I run the zkServer failed to bind to 8080 port.</p>
  
  <pre><code>Caused by: java.io.IOException: Failed to bind to /0.0.0.0:8080
      at org.eclipse.jetty.server.ServerConnector.openAcceptChannel(ServerConnector.java:346)
      at org.eclipse.jetty.server.ServerConnector.open(ServerConnector.java:308)
      at org.eclipse.jetty.server.AbstractNetworkConnector.doStart(AbstractNetworkConnector.java:80)
      at org.eclipse.jetty.server.ServerConnector.doStart(ServerConnector.java:236)
      at org.eclipse.jetty.util.component.AbstractLifeCycle.start(AbstractLifeCycle.java:68)
      at org.eclipse.jetty.server.Server.doStart(Server.java:396)
      at org.eclipse.jetty.util.component.AbstractLifeCycle.start(AbstractLifeCycle.java:68)
      at org.apache.zookeeper.server.admin.JettyAdminServer.start(JettyAdminServer.java:103)
      ... 5 more
  Caused by: java.net.BindException: Address already in use: bind
          at sun.nio.ch.Net.bind0(Native Method)
          at sun.nio.ch.Net.bind(Net.java:433)
          at sun.nio.ch.Net.bind(Net.java:425)
          at sun.nio.ch.ServerSocketChannelImpl.bind(ServerSocketChannelImpl.java:223)
          at sun.nio.ch.ServerSocketAdaptor.bind(ServerSocketAdaptor.java:74)
          at org.eclipse.jetty.server.ServerConnector.openAcceptChannel(ServerConnector.java:342)
          ... 12 more
  Unable to start AdminServer, exiting abnormally
  </code></pre>
  
  <p>My zoo.cfg file in like here:</p>
  
  <pre><code>tickTime=2000
  # The number of ticks that the initial 
  # synchronization phase can take
  initLimit=10
  # The number of ticks that can pass between 
  # sending a request and getting an acknowledgement
  syncLimit=5
  # the directory where the snapshot is stored.
  # do not use /tmp for storage, /tmp here is just 
  # example sakes.
  dataDir=/data
  # the port at which the clients will connect
  clientPort=2181
  # the maximum number of client connections.
  # increase this if you need to handle more clients
  #maxClientCnxns=60
  #
  # Be sure to read the maintenance section of the 
  # administrator guide before turning on autopurge.
  #
  # http://zookeeper.apache.org/doc/current/zookeeperAdmin.html#sc_maintenance
  #
  # The number of snapshots to retain in dataDir
  #autopurge.snapRetainCount=3
  # Purge task interval in hours
  # Set to "0" to disable auto purge feature
  #autopurge.purgeInterval=1
  </code></pre>
  
  <p>I don't know what is my problem?</p>