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

Rolling upgrade with HA


In the previous few recipes, we enabled high availability using different methods. In this section, we will look at how we can upgrade from one version of Hadoop to another.

The support for rolling upgrades became quite stable in Hadoop 2.4.1 and the clusters can be upgraded without a downtime. HA must be in place if there is a requirement for no downtime in the cluster. In HA, there are Namenodes, Datanodes, ZooKeeper, and Journal nodes. ZooKeeper and Journal nodes are generally stable and do not need an upgrade.

Getting ready

To complete this recipe, the user must have a running cluster with HA set up, as discussed previously. Download the latest stable Hadoop release and untar the package and update the sym-links to point to the newer versions. Refer to the Hadoop installation recipe for details on how the initial setup has been done. Secondly, make sure that the recipes before this have been completed or at least understood.

How to do it...

  1. Connect to the Namenodes...