Book Image

Redis 4.x Cookbook

Book Image

Redis 4.x Cookbook

Overview of this book

Redis is considered the world's most popular key-value store database. Its versatility and the wide variety of use cases it enables have made it a popular choice of database for many enterprises. Based on the latest version of Redis, this book provides both step-by-step recipes and relevant the background information required to utilize its features to the fullest. It covers everything from a basic understanding of Redis data types to advanced aspects of Redis high availability, clustering, administration, and troubleshooting. This book will be your great companion to master all aspects of Redis. The book starts off by installing and configuring Redis for you to get started with ease. Moving on, all the data types and features of Redis are introduced in detail. Next, you will learn how to develop applications with Redis in Java, Python, and the Spring Boot web framework. You will also learn replication tasks, which will help you to troubleshoot replication issues. Furthermore, you will learn the steps that need to be undertaken to ensure high availability on your cluster and during production deployment. Toward the end of the book, you will learn the topmost tasks that will help you to troubleshoot your ecosystem efficiently, along with extending Redis by using different modules.
Table of Contents (21 chapters)
Title Page
Dedication
Packt Upsell
Foreword
Contributors
Preface
13
Windows Environment Setup
Index

Testing Sentinel


We have demonstrated in the previous recipe how to set up an environment of one Redis master and two slaves, which is monitored by three Sentinels. In this recipe, we will do a couple of experiments in this environment and verify the Sentinels are doing their jobs correctly. We will also explain the master failover process in detail.

Getting ready…

You must finish the setup in the Setting up Sentinel section of this chapter. Additionally, you can refer to the table shown in the Getting ready section of the previous recipe, Setting up Sentinel.

How to do it...

To test the Redis Sentinel set up in the previous recipe, take the following steps:

  1. Triggering a master failover manually:
    1. Connect to one of the Sentinels using redis-cli; here we are connecting to Sentinel-2 (192.168.0.32):
192.168.0.32:26379> SENTINEL FAILOVER MYMASTER
OK
    1. Verify the old master 192.168.0.31 has been failed over and is now a slave:
192.168.0.31:26379> INFO REPLICATION
# Replication
role:slave
master_host...