What is Redis Sentinel?

What is Redis Sentinel?

Redis Sentinel is the high-availability solution for open-source Redis server. It provides monitoring of all Redis nodes and automatic failover should the master node become unavailable. This guide provides a sample configuration for a three-node Redis cluster.

What is the use of Redis Sentinel?

Redis Sentinel is the high availability solution offered by Redis, . In case of a failure in your Redis cluster, Sentinel will automatically detect the point of failure and bring the cluster back to stable mode without any human intervention.

How many Redis sentinels are there?

three Sentinel instances
You need at least three Sentinel instances for a robust deployment. The three Sentinel instances should be placed into computers or virtual machines that are believed to fail in an independent way.

Does ElastiCache use Sentinel?

AWS ElastiCache Instead of using Redis Sentinel, supported by pretty much every popular Redis client library, AWS decided to take a different approach. They implemented their own failover mechanism behind the scenes.

Can Redis have multiple masters?

You can deploy as many masters as you want, with any number of slaves each, but they will behave like a single separated cluster with their own memory space, and it will be your responsibility at the application layer to spread your keys properly using each of the masters, just as you would do in a Memcached multi-node …

Is Redis single point of failure?

A Redis cluster is simply a data sharding strategy. It automatically partitions data across multiple Redis nodes. It is an advanced version of Redis that achieves distributed storage and prevents a single point of failure.

What is the difference between Redis cluster and Sentinel?

So I’ll give you a brief introduction to both, so you get a better idea of what they are and when to use them. Redis Sentinel will basically monitor your master and slave instances and handle automatic failover, if any of them go down. Redis Cluster is what the name says, a clustering solution.

How create Redis Sentinel?

The Sentinel service has a similar configuration format as the Redis server. To configure it, use the /etc/redis-sentinel. conf self-documented configuration file. First, create a backup of the original file and open it for editing.

How do I connect to Redis Sentinel?

Connecting via Sentinel:

1. Get the address of the master host by using Sentinel and any Redis host: redis-cli -h -p 26379 sentinel get-master-addr-by-name | head -n 1.
2. Connect to the host with this address: redis-cli -h -a

Is Redis Sentinel a cluster?

Redis Sentinel is the name of the Redis high availability solution… It has nothing to do with Redis Cluster and is intended to be used by people that don’t need Redis Cluster, but simply a way to perform automatic fail over when a master instance is not functioning correctly.

Is Redis highly available?

High availability in Redis is achieved through master-slave replication. However, the most common HA solution that comes bundled with Redis is Redis Sentinels. Redis Sentinels run as a set of separate processes that in combination monitor Redis master-slave sets and provide automatic failover and reconfiguration.