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PostgreSQL Volume Expansion

This guide will give an overview on how KubeDB Ops-manager operator expand the volume of Postgres components such as Standalone, HA cluster etc.

Before You Begin

• You should be familiar with the following KubeDB concepts:
  • Postgres
  • PostgresOpsRequest

Volume Expansion Working Procedure

The following diagram shows how KubeDB Ops-manager operator expand the volumes of Postgres database components. Open the image in a new tab to see the enlarged version.

  

The Volume Expansion process consists of the following steps:

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

2. KubeDB community operator watches the Postgres CR.

3. When the operator finds a Postgres CR, it creates a PetSet and related necessary stuffs like pods, pvc, secret, service etc.

4. Each PetSet creates a Persistent Volume according to the Volume Claim Template provided in the Petset configuration. This Persistent Volume will be expanded by the KubeDB Ops-manager operator.

5. Then, in order to expand the volume of the various components (Standalone, HA cluster etc.) of the Postgres database, the user creates a PostgresOpsRequest CR with desired information.

6. KubeDB Ops-manager operator watches the PostgresOpsRequest CR.

7. When it finds a PostgresOpsRequest CR, it halts the Postgres object which is referred from the PostgresOpsRequest. So, the KubeDB Provisioner operator doesn’t perform any operations on the Postgres object during the volume expansion process.

8. Then the KubeDB Ops-manager operator will expand the persistent volume to reach the expected size defined in the PostgresOpsRequest CR.

9. After the successful expansion of the volume of the related PetSet Pods the KubeDB Ops-manager operator updates the new volume size in the Postgres object to reflect the updated state.

10. After the successful Volume Expansion of the Postgres components, the KubeDB Ops-manager operator resumes the Postgres object so that the KubeDB Provisioner operator resumes its usual operations.

In the next docs, we are going to show you a step-by-step guide on Volume Expansion of various Postgres database components using PostgresOpsRequest CRD.