What is YARN

Introduction to YARN: The Distributed Processing Framework

As an AI expert, it's crucial to understand the different tools and frameworks available in the world of distributed computing. One such framework that has gained immense popularity in recent years is YARN, short for Yet Another Resource Negotiator. As the name suggests, YARN serves as a key component in Apache Hadoop, enabling efficient and scalable processing of big data workloads. This article aims to provide a detailed overview of YARN and its significance in the world of distributed computing.

The Need for YARN: Challenges in Distributed Computing

Before we delve into the intricacies of YARN, let's first understand the challenges that it addresses. In traditional distributed computing frameworks like MapReduce, the cluster resource management and job scheduling were tightly coupled, which led to several drawbacks.

Firstly, the MapReduce framework assumed a static allocation of resources, where each job received a predetermined amount of memory and CPU. This approach resulted in underutilization of resources and limited scalability, especially when dealing with multiple workloads of varying sizes.

Secondly, the job scheduling decisions were made at the framework level, leaving limited control and flexibility for users to prioritize or manage their own jobs. This lack of flexibility often caused inefficiencies and delays in job execution.

Recognizing these challenges, the Apache Hadoop community introduced YARN as a revolutionary step towards addressing the limitations of the MapReduce framework and fueling the growth of distributed computing.

Understanding YARN: Key Concepts and Components

1. ResourceManager (RM)

The ResourceManager is the central authority in YARN, responsible for managing cluster resources and orchestrating the execution of various applications. It receives resource requests from the ApplicationMaster and allocates resources based on availability, fairness, and application-specific constraints. The ResourceManager maintains a global view of the cluster and ensures efficient resource utilization.

2. NodeManager (NM)

The NodeManager is responsible for managing resources on individual nodes in the cluster. It monitors resource utilization, reports them to the ResourceManager, and starts/stops containers to execute applications. The NodeManager also performs health checks, restarting containers if necessary, to ensure fault tolerance and stability.

3. ApplicationMaster (AM)

The ApplicationMaster is responsible for managing the execution and coordination of a specific application. Each application running on YARN has its own ApplicationMaster, which negotiates resources with the ResourceManager, communicates with the NodeManagers, and ensures the successful execution of tasks. The ApplicationMaster provides a level of isolation and controls the scheduling and monitoring of application-specific containers.

4. Container

A container in YARN represents a set of allocated resources on a specific node. It encapsulates the execution context for a task or process, including CPU, memory, disk, and network resources. Containers are managed and monitored by the NodeManager.

YARN's Architecture: How it Works

The architecture of YARN revolves around the separation of resource management and job scheduling. It introduces a flexible and scalable approach to distributed computing by providing a common framework for running multiple processing engines simultaneously.

When an application is submitted to YARN, it is comprised of multiple tasks or containers. The ResourceManager receives the application request and negotiates resources with the ApplicationMaster. Once the resources are allocated, the ApplicationMaster communicates with the NodeManagers to launch containers for executing tasks.

The ResourceManager maintains a global view of cluster resources, including information about available nodes and resources. It periodically communicates with the NodeManagers to gather live updates and make informed decisions for resource allocation.

The NodeManager, on the other hand, is responsible for monitoring and managing resources on individual nodes. It tracks resource utilization, communicates with the ResourceManager, and manages the lifecycle of containers. If a container fails or exceeds its allotted resources, the NodeManager restarts or terminates it, ensuring high availability and fault tolerance.

Overall, YARN's architecture provides a scalable and efficient platform for executing large-scale distributed applications, as it decouples resource management from application-specific job scheduling.

Benefits of YARN: Advantages for Distributed Computing

1. Scalability and Flexibility

YARN makes it easier to scale a Hadoop cluster by mapping resources to different applications dynamically. This flexibility allows for better resource utilization and the ability to handle a wide variety of workloads efficiently.

2. Multi-Tenancy Support

With YARN, multiple users can coexist on the same cluster, each with their own ApplicationMaster to manage their workloads. This multi-tenancy capability enables efficient sharing of cluster resources while providing isolation and prioritization for individual applications.

3. Integration with Hadoop Ecosystem

YARN is fully integrated with the Hadoop ecosystem and works seamlessly with other components like HDFS (Hadoop Distributed File System) and Hive, enabling a comprehensive data processing environment.

4. Support for Various Processing Engines

YARN acts as a universal processing platform, allowing different processing engines like MapReduce, Spark, and Flink to run simultaneously on the same cluster. This eliminates the need for separate infrastructure and enhances resource sharing.


YARN has revolutionized the world of distributed computing by providing a flexible, scalable, and efficient platform for processing big data workloads. Its separation of resource management and job scheduling has introduced a new level of scalability and multi-tenancy support, making it an indispensable component in the Apache Hadoop ecosystem.

By abstracting away the complexities of resource negotiation and management, YARN empowers organizations to unlock the true potential of their data, enabling them to derive valuable insights and drive data-driven decision-making. As an AI expert, understanding YARN and its capabilities is essential to harness the power of distributed computing and propel the field of artificial intelligence.