YARN (Yet Another Resource Negotiator) is a resource management system that is part of the Apache Hadoop ecosystem. It is responsible for allocating resources (such as CPU, memory, and storage) across the cluster and scheduling tasks to be executed on the available resources.
YARN was introduced in Hadoop 2.0 as a way to decouple the resource management and job scheduling functions from the data processing functions of Hadoop. It allows multiple data processing frameworks, such as MapReduce, Spark, and Flink, to run on the same cluster and share resources.
YARN consists of two main components: the resource manager and the node manager. The resource manager is responsible for allocating resources to applications and scheduling tasks to be executed on the node managers. The node managers are responsible for executing the tasks on the individual machines in the cluster and reporting the status of the tasks back to the resource manager.
YARN is an important component of the Hadoop ecosystem and is widely used in big data environments to manage resources and schedule tasks across a cluster of machines.