title: Hadoop DFS permission issue when running job
body: <p>I'm getting this following permission error, and am not sure why hadoop is trying to write to this particular folder:</p>
  
  <pre><code>hadoop jar /usr/lib/hadoop/hadoop-*-examples.jar pi 2 100000
  Number of Maps  = 2
  Samples per Map = 100000
  Wrote input for Map #0
  Wrote input for Map #1
  Starting Job
  org.apache.hadoop.security.AccessControlException: org.apache.hadoop.security.AccessControlException: Permission denied: user=myuser, access=WRITE, inode="/":hdfs:supergroup:drwxr-xr-x
  </code></pre>
  
  <p>Any idea why it is trying to write to the root of my hdfs?</p>
  
  <p><strong>Update:</strong> After temporarily setting hdfs root (/) to be 777 permissions, I seen that a "/tmp" folder is being written.  I suppose one option is to just create a "/tmp" folder with open permissions for all to write to, but it would be nice from a security standpoint if this is instead written to the user folder (i.e. /user/myuser/tmp)</p>