PostgreSQL Operator

by  Zalando

The PostgreSQL operator provisions and configures a PostgreSQL database cluster on top of Kubernetes. PostgreSQL is a powerful, open-source object-relational database system.

TL;DR:

  • Installing, updating or removing follows Kubestack's GitOps flow.
  • Instructions assume the default repository layout.
  • Bases can be consumed as-is or customized.
  • Step-by-step instructions are framework specific but bases can be used independently.

Install

  1. Vendor the base

    # Run these commands from the root of your Kubestack infra repository
    wget https://storage.googleapis.com/catalog.kubestack.com/postgresql-v1.5.0-kbst.0.zip
    unzip -d manifests/bases/ postgresql-v1.5.0-kbst.0.zip
    rm postgresql-v1.5.0-kbst.0.zip
  2. Include resource in apps overlay

    cd manifests/overlays/apps
    kustomize edit add resource ../../bases/postgresql/clusterwide
  3. Commit and push

    cd -
    git checkout -b add-postgresql
    git add manifests/bases/postgresql manifests/overlays/apps/kustomization.yaml
    git commit -m "Add postgresql v1.5.0-kbst.0 base"
    git push origin add-postgresql
  4. Review PR and merge

    Finally, review and merge the PR into master. Once it's been successfully applied against the Ops-Cluster set a prod-deploy tag to also apply the change against the Apps-Cluster.

Update

To update the operator delete the previously vendored base and then vendor the new version.

  1. Delete the previous vendored version

    # Run these commands from the root of your Kubestack infra repository
    rm -r manifests/bases/postgresql
  2. Vendor the new version

    # Run these commands from the root of your Kubestack infra repository
    wget https://storage.googleapis.com/catalog.kubestack.com/postgresql-v1.5.0-kbst.0.zip
    unzip -d manifests/bases/ postgresql-v1.5.0-kbst.0.zip
    rm postgresql-v1.5.0-kbst.0.zip
  3. Commit and push

    git checkout -b update-postgresql
    git add manifests/bases/postgresql
    git commit -m "Update postgresql base to v1.5.0-kbst.0"
    git push origin update-postgresql

Remove

Operators often create resources based on custom objects. When removing an operator, follow a two-step process to ensure operator provisioned resources are purged properly.

  1. Remove all the operator's custom objects.
  2. Once the operator had time to de-provision all resources it created, follow the instructions below to remove the operator itself.
  1. Remove resource from apps overlay

    cd manifests/overlays/apps
    kustomize edit remove resource ../../bases/postgresql/clusterwide
  2. Delete the vendored base from your repository

    cd -
    # Run these commands from the root of your Kubestack infra repository
    rm -r manifests/bases/postgresql
  3. Commit and push

    git checkout -b remove-postgresql
    git add manifests/bases/postgresql
    git commit -m "Remove postgresql base"
    git push origin remove-postgresql

Usage

Once the operator has been deployed to the Kubernetes cluster, you can use it to provision and operate one or more database clusters by creating a custom object of the operator's custom resource.

PostgreSQL Custom Object

Below is an example of a minimal PostgreSQL custom object to instruct the operator to provision a database cluster.

To get started, put the example below into a file called postgresql.yaml and add it to your application's manifests. Then apply the manifests including the postgresql.yaml as usual.

apiVersion: "acid.zalan.do/v1"
kind: postgresql
metadata:
name: acid-minimal-cluster
namespace: default
spec:
postgresql:
version: "10"
teamId: "ACID"
volume:
size: 1Gi
numberOfInstances: 2
users:
# admin user
admin:
- superuser
# application user
app_user: []
databases:
# db_name: user_name
app_db: app_user

Configuring your cluster

Make sure to configure name and namespace and the users and databases according to your application's requirements.

You can find additional information on these parameters and additional options in the upstream project's documentation.