What is Apache Hadoop YARN

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In this post, I am trying to explain about YARN, very popular in Hadoop interview questions. Although, I have already listed few very common Hadoop interview questions at top 20 Big Data interview questions.
What is YARN?
Apache YARN (Yet Another Resource Negotiator) is also known as Map Reduce2 is the cluster's resource management system. The objective of YARN was to split the resource management task into two separate daemons and one of them as global resource manager. The two daemons of YARN is Resource Manager and Node Manager.

The Resource Manager is per cluster level, means exactly one Resource Manager on one cluster and responsible to manage the resources across the cluster.

Node Manager runs on every nodes(machine) and responsible for containers, monitoring resource usage like CPU utilization, Memory, Network etc. and reporting the status back to the Resource Manager.

The Resource Manager has two main components -

• Scheduler
• Application Manager

The Scheduler performs the scheduling functions based on the requirements of the application, it allocates various resources such as Memory,CPU,Network etc. Currently three types of Schedule in Hadoop YARN, FIFO, Capacity Scheduler and Fair Scheduler.

The Application Master is responsible for accepting the job submission and negotiating appropriate resource containers from the Scheduler, tracking their status and monitoring for progress.

That's it about YARN.
If you are very new to Hadoop than, you can follow Hadoop Single Node Cluster setup and give a try of Hello World in Hadoop by executing simple MapReduce program.

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