Question

Under the MapReduce v1 architecture, which function is performed by the JobTracker?

A) Manages job execution on multiple slaves
B) Manages the file system namespace and metadata
C) Schedules and monitors MapReduce jobs
D) Executes map and reduce tasks

Answer 1

The JobTracker in MapReduce v1 architecture is responsible for scheduling and monitoring MapReduce jobs. It manages the distribution of tasks to TaskTrackers and ensures fault tolerance by rerunning failed tasks.

Step-by-step explanation:

Under the MapReduce v1 architecture, the function performed by the JobTracker is to schedules and monitors MapReduce jobs. Specifically, the JobTracker has two main responsibilities. First, it takes care of resource management, allocating tasks to available TaskTracker nodes within the cluster depending on the data locality and the available capacity on the TaskTrackers. Second, it tracks the execution of MapReduce tasks and provides fault tolerance by rerunning failed tasks.

As an integral part of the Hadoop framework, the JobTracker is crucial for the efficiency and reliability of MapReduce job processing. However, JobTracker was known to be a scalability bottleneck in larger clusters, which led to the development of YARN (Yet Another Resource Negotiator) in MapReduce v2 to handle resource management more effectively..