title: 8021 failed on connection exception: java.net.ConnectException: Connection refused at org.apache.hadoop.ipc.Client.wrapException(Client.java:1095)
body: <p>Hi I am trying to configure Hadoop 1.0. in pseudodistributed mode by following this blog.</p>
  
  <p><a href="http://hadoop-tutorial.blogspot.de/2010/11/running-hadoop-in-pseudo-distributed.html?showComment=1337083501000#c615470573579885293" rel="nofollow">http://hadoop-tutorial.blogspot.de/2010/11/running-hadoop-in-pseudo-distributed.html?showComment=1337083501000#c615470573579885293</a>.</p>
  
  <p>But when I run the pi example given in the hadoop distribution, I get the error mentioned in title. Can someone please help me and guide me how can I fix this problem. Also its a request that please suggest solution as well if possible along with pinpinting the problem. </p>
  
  <p>here is what i get by running jps</p>
  
  <pre><code>8322 Jps
  7611 SecondaryNameNode
  7474 DataNode
  7341 NameNode
  </code></pre>
  
  <p>Here is complete error message.</p>
  
  <pre><code>Number of Maps  = 10
  Samples per Map = 100
  Wrote input for Map #0
  Wrote input for Map #1
  Wrote input for Map #2
  Wrote input for Map #3
  Wrote input for Map #4
  Wrote input for Map #5
  Wrote input for Map #6
  Wrote input for Map #7
  Wrote input for Map #8
  Wrote input for Map #9
  Starting Job
  12/05/16 13:11:56 INFO ipc.Client: Retrying connect to server: localhost/127.0.0.1:8021. Already tried 0 time(s).
  12/05/16 13:11:57 INFO ipc.Client: Retrying connect to server: localhost/127.0.0.1:8021. Already tried 1 time(s).
  12/05/16 13:11:58 INFO ipc.Client: Retrying connect to server: localhost/127.0.0.1:8021. Already tried 2 time(s).
  12/05/16 13:11:59 INFO ipc.Client: Retrying connect to server: localhost/127.0.0.1:8021. Already tried 3 time(s).
  12/05/16 13:12:00 INFO ipc.Client: Retrying connect to server: localhost/127.0.0.1:8021. Already tried 4 time(s).
  12/05/16 13:12:01 INFO ipc.Client: Retrying connect to server: localhost/127.0.0.1:8021. Already tried 5 time(s).
  12/05/16 13:12:02 INFO ipc.Client: Retrying connect to server: localhost/127.0.0.1:8021. Already tried 6 time(s).
  12/05/16 13:12:03 INFO ipc.Client: Retrying connect to server: localhost/127.0.0.1:8021. Already tried 7 time(s).
  12/05/16 13:12:04 INFO ipc.Client: Retrying connect to server: localhost/127.0.0.1:8021. Already tried 8 time(s).
  12/05/16 13:12:05 INFO ipc.Client: Retrying connect to server: localhost/127.0.0.1:8021. Already tried 9 time(s).
  java.net.ConnectException: Call to localhost/127.0.0.1:8021 failed on connection exception: java.net.ConnectException: Connection refused
          at org.apache.hadoop.ipc.Client.wrapException(Client.java:1095)
          at org.apache.hadoop.ipc.Client.call(Client.java:1071)
          at org.apache.hadoop.ipc.RPC$Invoker.invoke(RPC.java:225)
          at org.apache.hadoop.mapred.$Proxy2.getProtocolVersion(Unknown Source)
          at org.apache.hadoop.ipc.RPC.getProxy(RPC.java:396)
          at org.apache.hadoop.ipc.RPC.getProxy(RPC.java:379)
          at org.apache.hadoop.mapred.JobClient.createRPCProxy(JobClient.java:480)
          at org.apache.hadoop.mapred.JobClient.init(JobClient.java:474)
          at org.apache.hadoop.mapred.JobClient.&lt;init&gt;(JobClient.java:457)
          at org.apache.hadoop.mapred.JobClient.runJob(JobClient.java:1260)
          at org.apache.hadoop.examples.PiEstimator.estimate(PiEstimator.java:297)
          at org.apache.hadoop.examples.PiEstimator.run(PiEstimator.java:342)
          at org.apache.hadoop.util.ToolRunner.run(ToolRunner.java:65)
          at org.apache.hadoop.examples.PiEstimator.main(PiEstimator.java:351)
          at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
          at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:57)
          at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
          at java.lang.reflect.Method.invoke(Method.java:601)
          at org.apache.hadoop.util.ProgramDriver$ProgramDescription.invoke(ProgramDriver.java:68)
          at org.apache.hadoop.util.ProgramDriver.driver(ProgramDriver.java:139)
          at org.apache.hadoop.examples.ExampleDriver.main(ExampleDriver.java:64)
          at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
          at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:57)
          at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
          at java.lang.reflect.Method.invoke(Method.java:601)
          at org.apache.hadoop.util.RunJar.main(RunJar.java:156)
  Caused by: java.net.ConnectException: Connection refused
          at sun.nio.ch.SocketChannelImpl.checkConnect(Native Method)
          at sun.nio.ch.SocketChannelImpl.finishConnect(SocketChannelImpl.java:701)
          at org.apache.hadoop.net.SocketIOWithTimeout.connect(SocketIOWithTimeout.java:206)
          at org.apache.hadoop.net.NetUtils.connect(NetUtils.java:656)
          at org.apache.hadoop.ipc.Client$Connection.setupConnection(Client.java:434)
          at org.apache.hadoop.ipc.Client$Connection.setupIOstreams(Client.java:560)
          at org.apache.hadoop.ipc.Client$Connection.access$2000(Client.java:184)
          at org.apache.hadoop.ipc.Client.getConnection(Client.java:1202)
          at org.apache.hadoop.ipc.Client.call(Client.java:1046)
          ... 24 more
  </code></pre>