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

Decommissioning DataNode


Similar to TaskTracker, there are situations when we need to temporarily disable a DataNode from the cluster, for example, because the storage space of the DataNode has been used up. In this recipe, we will outline steps to decommission a DataNode from a live Hadoop cluster.

Getting ready

We assume that our Hadoop has been configured properly.

Log in to the master node from the cluster administrator machine with the following command:

ssh hduser@master

Tip

For illustration purpose, we assume to decommission DataNode on host slave1 from our running Hadoop cluster.

How to do it...

Perform the following steps to decommission a live DataNode:

  1. Create the file $HADOOP_HOME/conf/dfs-exclude.txt with the following content:

    slave1

    Note

    The dfs-exclude.txt file contains the DataNode hostnames, one per line, that are to be decommissioned from the cluster.

  2. Add the following property to the file $HADOOP_HOME/conf/hdfs-site.xml:

    <property>
      <name>dfs.hosts.exclude</name&gt...