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Replace Sentinel Overview

This guide will give you an overview on how KubeDB Enterprise operator replaces sentinel of a Redis instance.

Before You Begin

• You should be familiar with the following KubeDB concepts:
  • Redis
  • RedisSentinel
  • RedisOpsRequest

How Replace Sentinel Process Works

The following diagram shows how KubeDB Enterprise operator replaces sentinel of Redis. Open the image in a new tab to see the enlarged version.

  

The replace sentinel process consists of the following steps:

1. At first, a user creates Redis and RedisSentinel Custom Resource (CR).

2. KubeDB Community operator watches the Redis and RedisSentinel CR.

3. When the operator finds a Redis CR, it creates a StatefulSet and related necessary stuff like appbinding, services, etc.

4. When the operator finds a RedisSentinel CR, it creates a StatefulSet and related necessary stuff like appbinding, services, etc.

5. Then, in order to replace the sentinel of the Redis database the user creates a new RedisSentinel object which will replace the old one and RedisOpsRequest CR with reference to the newly created sentinel.

6. KubeDB Enterprise operator watches the RedisOpsRequest CR.

7. When it finds a RedisOpsRequest CR, it pauses the Redis object which is referred from the RedisOpsRequest. So, the KubeDB Community operator doesn’t perform any operations on the Redis object during the upgrading process.

8. By looking at the target sentinel reference from RedisOpsRequest CR, KubeDB Enterprise operator removes current sentinel and add desired sentinel to the Redis object. Then it may delete the old RedisSentinel object if it is orphaned and user requested to remove it.

9. After successfully updating Redis object, the KubeDB Enterprise operator resumes the Redis object so that the KubeDB Community operator can resume its usual operations.

In the next docs, we are going to show a step-by-step guide on replacing sentinel of Redis database components using RedisOpsRequest CRD.

Next Steps

• Replace Sentinel of your database with a new Sentinel