During a citywide MapReduce job, something must assign map and reduce tasks to workers on the cluster. Which role description fits?
Select an answer to reveal the explanation.
Short Explanation
A foreperson hands out work packets; crews do the lifting. MapReduce uses a coordinator to assign map and reduce tasks to workers. Leaving every node to invent its own global plan is chaos, not a job.
Full Explanation
Classic MapReduce execution uses a master/coordinator component to schedule map and reduce tasks onto worker processes. Workers perform the assigned tasks; they do not each invent the whole job plan. NameNodes manage HDFS metadata and are not the place where all map/reduce functions run.