Book Image

Hadoop 2.x Administration Cookbook

By : Aman Singh
Book Image

Hadoop 2.x Administration Cookbook

By: Aman Singh

Overview of this book

Hadoop enables the distributed storage and processing of large datasets across clusters of computers. Learning how to administer Hadoop is crucial to exploit its unique features. With this book, you will be able to overcome common problems encountered in Hadoop administration. The book begins with laying the foundation by showing you the steps needed to set up a Hadoop cluster and its various nodes. You will get a better understanding of how to maintain Hadoop cluster, especially on the HDFS layer and using YARN and MapReduce. Further on, you will explore durability and high availability of a Hadoop cluster. You’ll get a better understanding of the schedulers in Hadoop and how to configure and use them for your tasks. You will also get hands-on experience with the backup and recovery options and the performance tuning aspects of Hadoop. Finally, you will get a better understanding of troubleshooting, diagnostics, and best practices in Hadoop administration. By the end of this book, you will have a proper understanding of working with Hadoop clusters and will also be able to secure, encrypt it, and configure auditing for your Hadoop clusters.
Table of Contents (20 chapters)
Hadoop 2.x Administration Cookbook
Credits
About the Author
About the Reviewers
www.PacktPub.com
Customer Feedback
Preface
Index

Configuring HDFS replication


For redundancy, it is important to have multiple copies of data. In HDFS, this is achieved by placing copies of blocks on different nodes. By default, the replication factor is 3, which means that for each block written to HDFS, there will be three copies in total on the nodes in the cluster.

It is important to make sure that the cluster is working fine and the user can perform file operations on the cluster.

Getting ready

Log in to any of the nodes in the cluster. It is best to use the edge node, as stated in Chapter 1, and switch to the user hadoop.

Create a simple text file named file1.txt using any of your favorite text editors, and write some content in it.

How to do it...

  1. ssh to the Namenode, which in this case is nn1.cluster1.com, and switch to user hadoop.

  2. Navigate to the /opt/cluster/hadoop/etc/hadoop directory. This is the directory where we installed Hadoop in Chapter 1, Hadoop Architecture and Deployment. If the user has installed it at a different location...