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which node will Hadoop first attempt to run the Map task?

You are running a job that will process a single InputSplit on a cluster which has no other jobs
currently running. Each node has an equal number of open Map slots. On which node will Hadoop
first attempt to run the Map task?

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A.
The node with the most memory

B.
The node with the lowest system load

C.
The node on which this InputSplit is stored

D.
The node with the most free local disk space

Explanation:
The TaskTrackers send out heartbeat messages to the JobTracker, usually every
few minutes, to reassure the JobTracker that it is still alive. These message also inform the

JobTracker of the number of available slots, so the JobTracker can stay up to date with where in
the cluster work can be delegated. When the JobTracker tries to find somewhere to schedule a
task within the MapReduce operations, it first looks for an empty slot on the same server that
hosts the DataNode containing the data, and if not, it looks for an empty slot on a machine in the
same rack.

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