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Upgrading Redis version Overview

This guide will give you an overview on how KubeDB Enterprise operator upgrade the version of Redis database.

Before You Begin

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

How Upgrade Process Works

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

  

The upgrading process consists of the following steps:

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

2. KubeDB Community operator watches the Redis CR.

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

4. Then, in order to upgrade the version of the Redis database the user creates a RedisOpsRequest CR with the desired version.

5. KubeDB Enterprise operator watches the RedisOpsRequest CR.

6. When it finds a RedisOpsRequest CR, it halts 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.

7. By looking at the target version from RedisOpsRequest CR, KubeDB Enterprise operator updates the images of all the StatefulSets. After each image update, the operator performs some checks such as if the oplog is synced and database size is almost same or not.

8. After successfully updating the StatefulSets and their Pods images, the KubeDB Enterprise operator updates the image of the Redis object to reflect the updated state of the database.

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

In the next doc, we are going to show a step by step guide on upgrading of a Redis database using upgrade operation.