Book Image

Learning YARN

Book Image

Learning YARN

Overview of this book

Today enterprises generate huge volumes of data. In order to provide effective services and to make smarter and more intelligent decisions from these huge volumes of data, enterprises use big-data analytics. In recent years, Hadoop has been used for massive data storage and efficient distributed processing of data. The Yet Another Resource Negotiator (YARN) framework solves the design problems related to resource management faced by the Hadoop 1.x framework by providing a more scalable, efficient, flexible, and highly available resource management framework for distributed data processing. This book starts with an overview of the YARN features and explains how YARN provides a business solution for growing big data needs. You will learn to provision and manage single, as well as multi-node, Hadoop-YARN clusters in the easiest way. You will walk through the YARN administration, life cycle management, application execution, REST APIs, schedulers, security framework and so on. You will gain insights about the YARN components and features such as ResourceManager, NodeManager, ApplicationMaster, Container, Timeline Server, High Availability, Resource Localisation and so on. The book explains Hadoop-YARN commands and the configurations of components and explores topics such as High Availability, Resource Localization and Log aggregation. You will then be ready to develop your own ApplicationMaster and execute it over a Hadoop-YARN cluster. Towards the end of the book, you will learn about the security architecture and integration of YARN with big data technologies like Spark and Storm. This book promises conceptual as well as practical knowledge of resource management using YARN.
Table of Contents (20 chapters)
Learning YARN
Credits
About the Authors
Acknowledgments
About the Reviewers
www.PacktPub.com
Preface
Index

Types of queues


As mentioned earlier in this chapter, YARN defines two schedulers (capacity and fair schedulers). These schedulers use their own implementation of the queue interface. The following diagram represents a class diagram for different queues defined in YARN:

CapacityScheduler Queue (CSQueue)

CSQueue is an interface that extends the Queue interface. It is defined in the org.apache.hadoop.yarn.server.resourcemanager.scheduler.capacity package. The CSQueue interface represents a queue structure for a node in the tree of hierarchical queues for CapacityScheduler.

The two classes that implement the CSQueue interface are as follows:

  • ParentQueue

  • LeafQueue

The properties associated with a CapacityScheduler queue are as follows:

  • yarn.scheduler.capacity.<queue-path>.capacity: This is a float value that specifies the capacity of the queue in percentage (%). At each level of queues (hierarchical queues), the sum of capacities for all queues must be equal to 100. In order to provide...