Hadoop YARN Resource Management

YARN (Yet Another Resource Negotiator) is the resource manager in Hadoop 2.x, responsible for managing the computing resources and scheduling tasks in the cluster. Its introduction solved the bottleneck issue of JobTracker in Hadoop 1.x by separating resource management and task scheduling, making Hadoop clusters more flexible and efficient.

YARN consists mainly of two components: the ResourceManager and the NodeManager. The ResourceManager is responsible for managing and scheduling resources for the entire cluster. It receives task requests from clients, allocates resources to different applications, and monitors the usage of cluster resources. The NodeManager, on the other hand, is responsible for managing resources and executing tasks on individual nodes. It communicates with the ResourceManager to report node resource usage and task execution status.

YARN’s resource management is divided into two levels: cluster-level resource management and application-level resource management. At the cluster level, the ResourceManager dynamically adjusts resource allocation and task scheduling based on the overall resources of the cluster and the resource usage of each node to ensure efficient cluster utilization and smooth task execution. At the application level, YARN provides ApplicationMaster to manage each application’s resource requests and task execution. Each application has an independent ApplicationMaster to interact with the ResourceManager and coordinate task execution.

YARN supports a variety of task schedulers such as Capacity Scheduler, Fair Scheduler, and FIFO Scheduler. Users can choose the appropriate scheduler based on their needs to manage the execution order and resource allocation of tasks. Additionally, YARN supports resource isolation and containerization, ensuring that each task runs in its own container for isolation and security.

Overall, YARN serves as the resource manager for Hadoop, providing powerful resource management and task scheduling functions for the cluster, enabling Hadoop clusters to handle large-scale data processing tasks more flexibly and efficiently. By configuring and utilizing YARN appropriately, users can fully leverage cluster resources to improve the efficiency and performance of data processing.