Yarn (Yet Another Resource Negotiator) - Hadoop Operating System

About

Yarn can be seen as the distributed operating system of Hadoop where all apps are build on top of it.

Yarn Hortonworks Image comes from Hortonworks

YARN was originally proposed (MR-279) and architected by one of the HortonWorks founders, Arun Murthy.

Yarn is the NextGen MapReduce (2.x). It maintains API compatibility with previous stable release (hadoop-1.x). All application should still run unchanged on top of YARN with just a recompile.

Yarn is able to run map reduce application but it is also possible to write other types of applications (having nothing to do with MapReduce). See Yarn - Application (app)

Hadoop YARN is part of Hadoop core and has as leader component the resource Manager. See Yarn - Architecture / Topology / Components

Documentation / Reference

Task Runner