Apache Yarn Interview Questions and Answers

Apache Yarn a platform responsible for managing computing resources in clusters and using them for scheduling users applications

1)What is Apache Hadoop YARN?

Answer)YARN stands for 'Yet Another Resource Negtiator'.YARN is a powerful and efficient feature rolled out as a part of Hadoop 2.0.YARN is a large scale distributed system for running big data applications.

2)What are the core concepts in YARN?

Answer)Resource Manager: As equivalent to JobTracker

Node Manager: As equivalent to TaskTracker

Application Manager: As equivalent to Jobs.

Containers: As quivalent to slots

YARN child: After submitting the application, dynamically application master launch YARN child to do the MapReduce tasks.

3)Is YARN a replacement of Hadoop MapReduce?

Answer)YARN is not a replacement of Hadoop but it is a more powerful and efficient technology that supports MapReduce and is also referred to as Hadoop 2.0 or MapReduce 2.

4)What are the additional benefits YARN brings in to Hadoop?

Answer)Effective utilization of the resources as multiple applications can be run in YARN all sharing a common resource.YARN is backward compatible so all the existing MapReduce jobs.Using YARN, one can even run applications that are not based on the MaReduce model

5)How can native libraries be included in YARN jobs?

Answer)There are two ways to include native libraries in YARN jobs-

1) By setting the -Djava.library.path on the command line

2) By setting the LD_LIBRARY_PATH in the .bashrc filewer

6)What is a container in YARN? Is it same as the child JVM in which the tasks on the nodemanager run or is it different?

Answer)It represents a resource (memory) on a single node at a given cluster.

A container is

supervised by the node manager

scheduled by the resource manager

One MR task runs in such container(s).