Question - Explain JobTracker in Hadoop
Answer -
JobTracker is a JVM process in Hadoop to submit and track MapReduce jobs.
JobTracker performs the following activities in Hadoop in a sequence –
- JobTracker receives jobs that a client application submits to the job tracker
- JobTracker notifies NameNode to determine data node
- JobTracker allocates TaskTracker nodes based on available slots.
- it submits the work on allocated TaskTracker Nodes,
- JobTracker monitors the TaskTracker nodes.
- When a task fails, JobTracker is notified and decides how to reallocate the task.