Understanding Hadoop YARN
Hadoop YARN (Yet Another Resource Negotiator) is the resource management and job scheduling component of the Apache Hadoop ecosystem. It is responsible for managing the computing resources in a Hadoop cluster and scheduling the execution of applications on those resources.
YARN was introduced in Hadoop 2.0 to address the limitations of the previous job scheduling mechanism in Hadoop 1.0, known as the JobTracker. YARN provides a more scalable, flexible, and robust resource management system that can handle a wide range of applications, including batch processing, interactive queries, real-time streaming, and machine learning.
The key components of YARN are:
ResourceManager
The ResourceManager is the central authority that manages the computing resources in the Hadoop cluster. It is responsible for allocating resources to applications, monitoring their execution, and ensuring fair and efficient utilization of the cluster resources.
NodeManager
The NodeManager is the agent running on each node in the Hadoop cluster. It is responsible for launching and monitoring the execution of application containers on the local node, and reporting the resource usage and status to the ResourceManager.
Application Master
The Application Master is a per-application component that negotiates resources from the ResourceManager and works with the NodeManagers to execute the application's tasks on the allocated resources.
YARN provides a flexible and extensible application programming model that allows developers to write custom applications that can be submitted and executed on the Hadoop cluster. These applications can be written in a variety of programming languages, including Java, Python, and Scala, and can be designed to handle a wide range of data processing tasks, from batch processing to real-time streaming.
graph TD
A[Client] --> B[ResourceManager]
B --> C[NodeManager]
C --> D[Application Master]
D --> E[Container]
The above diagram illustrates the high-level architecture of Hadoop YARN and the interactions between its key components.