What happens if a Mapper on one node goes into an infinite loop while running a MapReduce job?

A.
After a period of time, the JobTracker will restart the TaskTracker on the node on which the
map task is running

B.
The Mapper will run indefinitely; the TaskTracker must be restarted to kill it

C.
The job will immediately fail.

D.
After a period of time, the TaskTracker will kill the Map Task.

Explanation:
* The TaskTracker nodes are monitored. If they do not submit heartbeat signals
often enough, they are deemed to have failed and the work is scheduled on a different
TaskTracker.
* A TaskTracker will notify the JobTracker when a task fails. The JobTracker decides what to do
then: it may resubmit the job elsewhere, it may mark that specific record as something to avoid,
and it may may even blacklist the TaskTracker as unreliable.