Redis Sentinel — High Availability: Everything you need to know from DEV to PROD: Complete Guide

Amila Iddamalgoda
13 min readApr 21, 2018

What does the term ‘Redis’ actually mean?

It means REmote DIctionary Server.

Alright! There are plenty of different Redis articles out there, but I wanted to share my experience as a developer with Redis by creating an “all in one proper article” covering the most essential and important stuff that is needed and helpful for a developer or a devops engineer to build a Highly Available Redis cluster with Sentinel.

So let’s get started…

Redis, which is an open source in memory data structure store, is a very popular selection among developers used for caching purposes, as a message broker and also mainly used as a NoSQL Key-Value database for different use cases.

In this post, I’m going to specifically discuss and demo about Redis along with Master/Slave Replication, High availability (Redis Sentinel), Automatic Failover , some production level optimizing tips and monitoring aspects. In addition, along with these topics I’ll be mentioning the issues and the errors that I faced during implementation of Redis Sentinel with Ubuntu. Following shows the OS version and Redis version details.

OS version: Ubuntu 16.04.1 LTS (GNU/Linux 4.4.0-119-generic x86_64)
Redis Version: 4.0.9

Additionally, I want to highlight that the Redis documentation is very informative and it’s ‘the go to place’ if you need any further clarification on Redis.

Moving forward to Redis basics; Redis is a in-memory database, simply which means Redis runs on RAM. You also need to know that Redis supports several data structures such as strings, hashes, lists, sets, sorted sets with range queries, bitmaps. Furthermore, it also supports atomic operations such as, appending to a string, incrementing the value in a hash, pushing an element to a list and etc.

Well, Let’s get things started with Redis High Availability.

How Redis offers High Availability and Automatic Failover ?

Redis sentinel is the high availability solution offered by Redis. In case of a failure in your Redis cluster, Sentinel will automatically…

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Amila Iddamalgoda

• Full-Stack Engineer • AWS Certified Solutions Architect — Associate • Technology Enthusiast https://www.linkedin.com/in/amila-iddamalgoda-81055a61/