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PgBouncer Horizontal Scaling

This guide will give an overview on how KubeDB Ops-manager operator scales up or down PgBouncer replicas of PetSet.

Before You Begin

• You should be familiar with the following KubeDB concepts:
  • PgBouncer
  • PgBouncerOpsRequest

How Horizontal Scaling Process Works

The following diagram shows how KubeDB Ops-manager operator scales up or down PgBouncer 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 PgBouncer Custom Resource (CR).

2. KubeDB Provisioner operator watches the PgBouncer CR.

3. When the operator finds a PgBouncer CR, it creates PetSet and related necessary stuff like secrets, services, etc.

4. Then, in order to scale the PetSet of the PgBouncer database the user creates a PgBouncerOpsRequest CR with desired information.

5. KubeDB Ops-manager operator watches the PgBouncerOpsRequest CR.

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

7. Then the KubeDB Ops-manager operator will scale the related PetSet Pods to reach the expected number of replicas defined in the PgBouncerOpsRequest CR.

8. After the successfully scaling the replicas of the related PetSet Pods, the KubeDB Ops-manager operator updates the number of replicas in the PgBouncer object to reflect the updated state.

9. After the successful scaling of the PgBouncer replicas, the KubeDB Ops-manager operator resumes the PgBouncer object so that the KubeDB Provisioner operator resumes its usual operations.

In the next docs, we are going to show a step-by-step guide on horizontal scaling of PgBouncer using PgBouncerOpsRequest CRD.