Book Image

Mastering Apache Storm

By : Ankit Jain
Book Image

Mastering Apache Storm

By: Ankit Jain

Overview of this book

Apache Storm is a real-time Big Data processing framework that processes large amounts of data reliably, guaranteeing that every message will be processed. Storm allows you to scale your data as it grows, making it an excellent platform to solve your big data problems. This extensive guide will help you understand right from the basics to the advanced topics of Storm. The book begins with a detailed introduction to real-time processing and where Storm fits in to solve these problems. You’ll get an understanding of deploying Storm on clusters by writing a basic Storm Hello World example. Next we’ll introduce you to Trident and you’ll get a clear understanding of how you can develop and deploy a trident topology. We cover topics such as monitoring, Storm Parallelism, scheduler and log processing, in a very easy to understand manner. You will also learn how to integrate Storm with other well-known Big Data technologies such as HBase, Redis, Kafka, and Hadoop to realize the full potential of Storm. With real-world examples and clear explanations, this book will ensure you will have a thorough mastery of Apache Storm. You will be able to use this knowledge to develop efficient, distributed real-time applications to cater to your business needs.
Table of Contents (19 chapters)
Title Page
About the Author
About the Reviewers
Customer Feedback

Rebalance the parallelism of a topology

As explained in the previous chapter, one of the key features of Storm is that it allows us to modify the parallelism of a topology at runtime. The process of updating a topology parallelism at runtime is called rebalance.

There are two ways to rebalance the topology:

  • Using Storm Web UI
  • Using Storm CLI

The Storm Web UI was covered in the previous chapter. This section covers how we can rebalance the topology using the Storm CLI tool. Here are the commands that we need to execute on Storm CLI to rebalance the topology:

> bin/storm rebalance [TopologyName] -n [NumberOfWorkers] -e [Spout]=[NumberOfExecutos] -e [Bolt1]=[NumberOfExecutos] [Bolt2]=[NumberOfExecutos]

The rebalance command will first deactivate the topology for the duration of the message timeout and then redistribute the workers evenly around the Storm cluster. After a few seconds or minutes, the topology will revert to the previous state of activation and restart the processing of input streams...