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PerconaXtraDB Horizontal Scaling

This guide will give an overview on how KubeDB Enterprise operator scales up or down PerconaXtraDB Cluster.

Before You Begin

• You should be familiar with the following KubeDB concepts:
  • PerconaXtraDB
  • PerconaXtraDBOpsRequest

How Horizontal Scaling Process Works

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

  

The Horizontal scaling process consists of the following steps:

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

2. KubeDB Community operator watches the PerconaXtraDB CR.

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

4. Then, in order to scale the PerconaXtraDB database the user creates a PerconaXtraDBOpsRequest CR with desired information.

5. KubeDB Enterprise operator watches the PerconaXtraDBOpsRequest CR.

6. When it finds a PerconaXtraDBOpsRequest CR, it pauses the PerconaXtraDB object which is referred from the PerconaXtraDBOpsRequest. So, the KubeDB Community operator doesn’t perform any operations on the PerconaXtraDB object during the horizontal scaling process.

7. Then the KubeDB Enterprise operator will scale the related StatefulSet Pods to reach the expected number of replicas defined in the PerconaXtraDBOpsRequest CR.

8. After the successfully scaling the replicas of the StatefulSet Pods, the KubeDB Enterprise operator updates the number of replicas in the PerconaXtraDB object to reflect the updated state.

9. After the successful scaling of the PerconaXtraDB replicas, the KubeDB Enterprise operator resumes the PerconaXtraDB object so that the KubeDB Community operator resumes its usual operations.

In the next docs, we are going to show a step by step guide on horizontal scaling of PerconaXtraDB database using PerconaXtraDBOpsRequest CRD.