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

Configuring speculative execution


Speculative execution is a proactive performance boosting strategy used by JobTracker to execute one task on two TaskTracker instances. When either of these tasks finishes, the other task will be killed. By default, speculative execution is on.

Speculative execution can be helpful to improve the performance of MapReduce jobs by reducing the execution time for slowly progressing tasks. For example, on heterogeneous Hadoop clusters with different hardware configurations, low performance computing nodes can greatly prolong the execution time of a MapReduce job. Speculative execution can remedy this problem by prioritizing the high performance nodes for MapReduce tasks execution. Hence, the MapReduce execution time can be shortened.

On the other hand, speculative execution can negatively affect the performance of the cluster when a lot of resources are used for speculative execution. For example, many tasks will have to wait for slots that are used for speculative...