Page 41 - Building Big Data Applications

Chapter 2 Infrastructure and technology 35

Task
Tracker

Task Task
Client
Task
Job
Tracker Tracker
Client
Task Task

Task
MapReduce Status
Tracker
Job Submission
Task Task

FIGURE 2.8 MapReduce classic e JobTracker architecture. Image sourcedApache Foundation.

there are two modules a global ResourceManager (RM) and per-application
ApplicationMaster (AM) (Fig. 2.9).
The primary components and their focus areas are as follows:
ResourceManager (RM)
Has two main components
Scheduler
The Scheduler is responsible for allocating resources to the various
running applications and manages the constraints of capacities, availabil-
ity, and resource queues
The Scheduler will be responsible for purely schedule management and
will be working on scheduling based on resource containers, which
specify memory, disk, and CPU
Scheduler will not assume restarting of failed tasks either due to applica-
tion failure or hardware failures
Applications Manager (AM)
Responsible for accepting jobsubmissions
Negotiates the first container for executing the application-specific
ApplicationMaster
Provides the service for restarting the ApplicationMaster container on
failure
Applications Manager has three sub components:
Scheduler negotiatordComponent responsible for negotiating the re-
sources for the AM with the Scheduler