title: Hadoop client not able to connect to server
body: <p>I set up a 2-node Hadoop cluster, and running start-df.sh and start-yarn.sh works nicely (i.e. all expected services are running, no errors in the logs).</p>
  
  <p>However, when I actually try to run an application, several tasks fail:</p>
  
  <blockquote>
    <p>15/04/01 15:27:53 INFO mapreduce.Job: Task Id :
    attempt_1427894767376_0001_m_000008_2, Status : FAILED</p>
  </blockquote>
  
  <p>I checked the yarn and datanode logs, but nothing is reported there. 
  In the userlogs, the syslogs files on the slave node all contain the following error message:</p>
  
  <blockquote>
    <p>2015-04-01 15:27:21,077 INFO [main] org.apache.hadoop.ipc.Client:
    Retrying connect to server:
    slave.domain.be./127.0.1.1:53834. Already tried 9 time(s);
    retry policy is RetryUpToMaximumCountWithFixedSleep(maxRetries=10,
    sleepTime=1000 MILLISECONDS) 
    2015-04-01 15:27:21,078 WARN [main]
    org.apache.hadoop.mapred.YarnChild: 
    Exception running child :
    java.net.ConnectException: Call From
    slave.domain.be./127.0.1.1 to
    slave.domain.be.:53834 failed on connection exception:
    java.net.ConnectException: Connection refused; For more details see: 
    <a href="http://wiki.apache.org/hadoop/ConnectionRefused" rel="nofollow">http://wiki.apache.org/hadoop/ConnectionRefused</a>   at
    sun.reflect.NativeConstructorAccessorImpl.newInstance0(Native Method)</p>
  </blockquote>
  
  <p>So the problem is that the slave cannot connect to itself..</p>
  
  <p>I checked whether there is a process running on the slave node listening at port 53834, but there is none.
  However, all 'expected' ports are being listened on (50020,50075,..). Nowhere in my configuration I have used port 53834. It's always a different port on different runs.</p>
  
  <p>Any ideas on fixing this issue?</p>