Book Image

Apache Oozie Essentials

By : Jagat Singh
Book Image

Apache Oozie Essentials

By: Jagat Singh

Overview of this book

As more and more organizations are discovering the use of big data analytics, interest in platforms that provide storage, computation, and analytic capabilities is booming exponentially. This calls for data management. Hadoop caters to this need. Oozie fulfils this necessity for a scheduler for a Hadoop job by acting as a cron to better analyze data. Apache Oozie Essentials starts off with the basics right from installing and configuring Oozie from source code on your Hadoop cluster to managing your complex clusters. You will learn how to create data ingestion and machine learning workflows. This book is sprinkled with the examples and exercises to help you take your big data learning to the next level. You will discover how to write workflows to run your MapReduce, Pig ,Hive, and Sqoop scripts and schedule them to run at a specific time or for a specific business requirement using a coordinator. This book has engaging real-life exercises and examples to get you in the thick of things. Lastly, you’ll get a grip of how to embed Spark jobs, which can be used to run your machine learning models on Hadoop. By the end of the book, you will have a good knowledge of Apache Oozie. You will be capable of using Oozie to handle large Hadoop workflows and even improve the availability of your Hadoop environment.
Table of Contents (16 chapters)
Apache Oozie Essentials
Credits
About the Author
About the Reviewers
www.PacktPub.com
Preface
Index

Types of nodes


Workflow is composed of nodes; the logical DAG of nodes represents what part of the work is done by Oozie. Each node does a specified work and on success moves to one node or moves to another node on failure. For example, on success it goes to the OK node and on failure it goes to the Kill node.

Nodes in the Oozie Workflow are of the following types:

  • Control flow nodes

  • Action nodes

Let's discuss them in detail.

Control flow nodes

These nodes are responsible for defining start, end, and control flow of what to do inside the Workflow. These can be one of following:

  • Start node

  • End node

  • Kill node

  • Decision node

  • Fork and Join node

You have already seen the examples of the Start, End, and Kill nodes. In the context of programming, we can say that Decision nodes represent the switch or if else conditions. Fork and Join nodes represent the parallel branches of code.

Let's see a sample syntax for Decision and Fork/Join nodes next.

Here's the general syntax for a Decision node:

<workflow-app name...