title: Task tracker not running,the job is scheduled but doesnt run. how to fix?
body: <p>I have been running some benchmarks and i am new to hadoop and hdfs. I have got the setup and things running and they were working fine. But now i am faced with this issue, jps on the master shows
  1. secondary name node
  2. job tracker
  but not the name node and task tracker.</p>
  
  <p>similarly jps on the slave nodes shows only name node, but task tracker is not running.</p>
  
  <p>I usually run the job as the user and not root, but mistakenly i ran it as root and then when i exited and ran the job as user, i found the job doesn't start. then with jps i found the task tracker is not running.</p>
  
  <p>I am new to hdfs, and not sure how to debug and solve this, it would be great if you can give some pointers/help on this one, i did try google and couldnt find relevant answers.</p>
  
  <p>Edit: I tried clearing tmp files, killing obsolete java process and restarting. still i get the same issue.
  Thanks.</p>