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Redis Horizontal Scaling

This guide will give an overview on how KubeDB Ops Manager scales up or down of Redis cluster database for both the number of replicas and shards.

Before You Begin

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

How Horizontal Scaling Process Works

The following diagram shows how KubeDB Ops Manager scales up or down Redis database components. Open the image in a new tab to see the enlarged version.

  

The updating process consists of the following steps:

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

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

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

4. Then, in order to scale the number of replica or shard for the Redis cluster database the user creates a RedisOpsRequest CR with desired information.

5. Then, in order to scale the number of replica for the RedisSentinel instance the user creates a RedisSentinelOpsRequest CR with desired information.

6. KubeDB Enterprise operator watches the RedisOpsRequest and RedisSentinelOpsRequest CR.

7. 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 scaling process.

8. When it finds a RedisSentinelOpsRequest CR, it halts the RedisSentinel object which is referred from the RedisSentinelOpsRequest. So, the KubeDB Community operator doesn’t perform any operations on the RedisSentinel object during the scaling process.

9. Then the Redis Ops-manager operator will scale the related PetSet Pods to reach the expected number of shards and/or replicas defined in the RedisOpsRequest or RedisSentinelOpsRequest CR.

10. After the successful scaling the replicas of the related PetSet Pods, the KubeDB Ops-manager operator updates the number of replicas/shards in the Redis/RedisSentinel object to reflect the updated state.

11. After successfully updating of Redis/RedisSentinel object, the KubeDB Enterprise operator resumes the Redis/RedisSentinel 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 updating of a Redis database using scale operation.