title: Hadoop JAR: "JobTracker is in safe mode"
body: <p>I'm trying to run the Wordcount example and I got this thrown at my face:</p>
  
  <pre><code>13/12/01 19:46:49 ERROR security.UserGroupInformation: PriviledgedActionException
  as:player cause:org.apache.hadoop.ipc.RemoteException: 
  org.apache.hadoop.mapred.SafeModeException: JobTracker is in safe mode
      at org.apache.hadoop.mapred.JobTracker.checkSafeMode(JobTracker.java:5188)
      at org.apache.hadoop.mapred.JobTracker.getStagingAreaDir(JobTracker.java:3677)
      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:606)
      at org.apache.hadoop.ipc.RPC$Server.call(RPC.java:587)
      at org.apache.hadoop.ipc.Server$Handler$1.run(Server.java:1432)
      at org.apache.hadoop.ipc.Server$Handler$1.run(Server.java:1428)
      at java.security.AccessController.doPrivileged(Native Method)
      at javax.security.auth.Subject.doAs(Subject.java:415)
      at org.apache.hadoop.security.UserGroupInformation.doAs(UserGroupInformation.java:1190)
      at org.apache.hadoop.ipc.Server$Handler.run(Server.java:1426)
  
  org.apache.hadoop.ipc.RemoteException: org.apache.hadoop.mapred.SafeModeException: JobTracker is in safe mode
      at org.apache.hadoop.mapred.JobTracker.checkSafeMode(JobTracker.java:5188)
      at org.apache.hadoop.mapred.JobTracker.getStagingAreaDir(JobTracker.java:3677)
      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:606)
      at org.apache.hadoop.ipc.RPC$Server.call(RPC.java:587)
      at org.apache.hadoop.ipc.Server$Handler$1.run(Server.java:1432)
      at org.apache.hadoop.ipc.Server$Handler$1.run(Server.java:1428)
      at java.security.AccessController.doPrivileged(Native Method)
      at javax.security.auth.Subject.doAs(Subject.java:415)
      at org.apache.hadoop.security.UserGroupInformation.doAs(UserGroupInformation.java:1190)
      at org.apache.hadoop.ipc.Server$Handler.run(Server.java:1426)
  
      at org.apache.hadoop.ipc.Client.call(Client.java:1113)
      at org.apache.hadoop.ipc.RPC$Invoker.invoke(RPC.java:229)
      at org.apache.hadoop.mapred.$Proxy2.getStagingAreaDir(Unknown Source)
      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:606)
      at org.apache.hadoop.io.retry.RetryInvocationHandler.invokeMethod(RetryInvocationHandler.java:85)
      at org.apache.hadoop.io.retry.RetryInvocationHandler.invoke(RetryInvocationHandler.java:62)
      at org.apache.hadoop.mapred.$Proxy2.getStagingAreaDir(Unknown Source)
      at org.apache.hadoop.mapred.JobClient.getStagingAreaDir(JobClient.java:1309)
      at org.apache.hadoop.mapreduce.JobSubmissionFiles.getStagingDir(JobSubmissionFiles.java:102)
      at org.apache.hadoop.mapred.JobClient$2.run(JobClient.java:942)
      at org.apache.hadoop.mapred.JobClient$2.run(JobClient.java:936)
      at java.security.AccessController.doPrivileged(Native Method)
      at javax.security.auth.Subject.doAs(Subject.java:415)
      at org.apache.hadoop.security.UserGroupInformation.doAs(UserGroupInformation.java:1190)
      at org.apache.hadoop.mapred.JobClient.submitJobInternal(JobClient.java:936)
      at org.apache.hadoop.mapreduce.Job.submit(Job.java:550)
      at org.apache.hadoop.mapreduce.Job.waitForCompletion(Job.java:580)
      at org.apache.hadoop.examples.WordCount.main(WordCount.java:82)
      at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
      at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:57)
      at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
      at java.lang.reflect.Method.invoke(Method.java:606)
      at org.apache.hadoop.util.ProgramDriver$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:606)
      at org.apache.hadoop.util.RunJar.main(RunJar.java:160)
  </code></pre>
  
  <p>I've tried a few configurations in <code>mapred-default.xml</code>, but without success.</p>