Book Image

Hadoop Beginner's Guide

Book Image

Hadoop Beginner's Guide

Overview of this book

Data is arriving faster than you can process it and the overall volumes keep growing at a rate that keeps you awake at night. Hadoop can help you tame the data beast. Effective use of Hadoop however requires a mixture of programming, design, and system administration skills."Hadoop Beginner's Guide" removes the mystery from Hadoop, presenting Hadoop and related technologies with a focus on building working systems and getting the job done, using cloud services to do so when it makes sense. From basic concepts and initial setup through developing applications and keeping the system running as the data grows, the book gives the understanding needed to effectively use Hadoop to solve real world problems.Starting with the basics of installing and configuring Hadoop, the book explains how to develop applications, maintain the system, and how to use additional products to integrate with other systems.While learning different ways to develop applications to run on Hadoop the book also covers tools such as Hive, Sqoop, and Flume that show how Hadoop can be integrated with relational databases and log collection.In addition to examples on Hadoop clusters on Ubuntu uses of cloud services such as Amazon, EC2 and Elastic MapReduce are covered.
Table of Contents (19 chapters)
Hadoop Beginner's Guide
Credits
About the Author
About the Reviewers
www.PacktPub.com
Preface
Index

MapReduce management


As we saw in the previous chapter, the MapReduce framework is generally more tolerant of problems and failures than HDFS. The JobTracker and TaskTrackers have no persistent data to manage and, consequently, the management of MapReduce is more about the handling of running jobs and tasks than servicing the framework itself.

Command line job management

The hadoop job command-line tool is the primary interface for this job management. As usual, type the following to get a usage summary:

$ hadoop job --help

The options to the command are generally self-explanatory; it allows you to start, stop, list, and modify running jobs in addition to retrieving some elements of job history. Instead of examining each individually, we will explore the use of several of these subcommands together in the next section.

Have a go hero – command line job management

The MapReduce UI also provides access to a subset of these capabilities. Explore the UI and see what you can and cannot do from the...