YARN - Yet Another Resource Negotiator!

A typical need in the majority of distributed processing engines is the necessity to oversee resources. Hadoop YARN deals with such functions that are critical. The Hadoop world began with Map Reduce as the first data processing framework, but afterwards improved to include various project tasks. The majority of these projects have the same flow with regards to resource management. Basically, YARN abstracts a great deal of these projects and deals with the complex work for you. There are applications in the current Hadoop ecosystem that are composed in written format as YARN applications – as if each application converses with yarn and informs it what it needs to ensure the job is done. On the other hand, Yarn finds out what’s available and what to designate to a specific task.

https://hadoop.apache.org/docs/current/hadoop-yarn/hadoop-yarn-site/YARN.html