In Hadoop for submitting and tracking MapReduce jobs, JobTracker is used. Job tracker run on its own JVM process
Job Tracker performs following actions in Hadoop
* Client application submit jobs to the job tracker
* JobTracker communicates to the Name mode to determine data location
* Near the data or with available slots JobTracker locates TaskTracker nodes
* On chosen TaskTracker Nodes, it submits the work
* When a task fails, Job tracker notifies and decides what to do then.
* The TaskTracker nodes are monitored by JobTracker
