Book Image

Hadoop Operations and Cluster Management Cookbook

By : Shumin Guo
Book Image

Hadoop Operations and Cluster Management Cookbook

By: Shumin Guo

Overview of this book

<p>We are facing an avalanche of data. The unstructured data we gather can contain many insights that could hold the key to business success or failure. Harnessing the ability to analyze and process this data with Hadoop is one of the most highly sought after skills in today's job market. Hadoop, by combining the computing and storage powers of a large number of commodity machines, solves this problem in an elegant way!</p> <p>Hadoop Operations and Cluster Management Cookbook is a practical and hands-on guide for designing and managing a Hadoop cluster. It will help you understand how Hadoop works and guide you through cluster management tasks.</p> <p>This book explains real-world, big data problems and the features of Hadoop that enables it to handle such problems. It breaks down the mystery of a Hadoop cluster and will guide you through a number of clear, practical recipes that will help you to manage a Hadoop cluster.</p> <p>We will start by installing and configuring a Hadoop cluster, while explaining hardware selection and networking considerations. We will also cover the topic of securing a Hadoop cluster with Kerberos, configuring cluster high availability and monitoring a cluster. And if you want to know how to build a Hadoop cluster on the Amazon EC2 cloud, then this is a book for you.</p>
Table of Contents (15 chapters)
Hadoop Operations and Cluster Management Cookbook
Credits
About the Author
About the Reviewers
www.PacktPub.com
Preface
Index

Recovering from NameNode failure


The NameNode in a Hadoop cluster keeps track of the metadata for the whole HDFS filesystem. Unfortunately, as of this book's writing, the NameNode in the current stable version of Hadoop is a single point of failure. If the metadata of the NameNode is corrupted, for example, due to hard drive failure, the whole cluster will become unavailable. So, it is important to safeguard the NameNode from these disastrous failures.

There are multiple ways we can increase the resilience of a HDFS cluster. In this recipe, we will show you how to configure a SecondaryNameNode as a backup NameNode and how to recover from NameNode failures.

Getting ready

We assume that our Hadoop cluster has been properly configured, and we have one machine, master1, as the NameNode and a second machine, master2, to run the SecondaryNameNode.

Note

Please be prepared that a NameNode failure can cause the cluster to halt. It might take some time to recover from the failure.

How to do it...

The first...