Chapter 1. Starting with YARN Basics

In early 2006, Apache Hadoop was introduced as a framework for the distributed processing of large datasets stored across clusters of computers, using a programming model. Hadoop was developed as a solution to handle big data in a cost effective and easiest way possible. Hadoop consisted of a storage layer, that is, Hadoop Distributed File System (HDFS) and the MapReduce framework for managing resource utilization and job execution on a cluster. With the ability to deliver high performance parallel data analysis and to work with commodity hardware, Hadoop is used for big data analysis and batch processing of historical data through MapReduce programming.

With the exponential increase in the usage of social networking sites such as Facebook, Twitter, and LinkedIn and e-commerce sites such as Amazon, there was the need of a framework to support not only MapReduce batch processing, but real-time and interactive data analysis as well. Enterprises should be able to execute other applications over the cluster to ensure that cluster capabilities are utilized to the fullest. The data storage framework of Hadoop was able to counter the growing data size, but resource management became a bottleneck. The resource management framework for Hadoop needed a new design to solve the growing needs of big data.

YARN, an acronym for Yet Another Resource Negotiator, has been introduced as a second-generation resource management framework for Hadoop. YARN is added as a subproject of Apache Hadoop. With MapReduce focusing only on batch processing, YARN is designed to provide a generic processing platform for data stored across a cluster and a robust cluster resource management framework.

In this chapter, we will cover the following topics:

• Introduction to MapReduce v1
• Shortcomings of MapReduce v1
• An overview of the YARN components
• The YARN architecture
• How YARN satisfies big data needs
• Projects powered by YARN