Create a PostgreSQL Cluster With Custom Password Generation Policy on KubeBlocks

This guide explains how to deploy a PostgreSQL cluster in KubeBlocks with a custom password generation policy for the root user. By defining specific password rules, you can ensure strong, secure credentials for your cluster.

Prerequisites

Before proceeding, ensure the following:

• Environment Setup:
  • A Kubernetes cluster is up and running.
  • The kubectl CLI tool is configured to communicate with your cluster.
  • KubeBlocks CLI and KubeBlocks Operator are installed. Follow the installation instructions here.
• Namespace Preparation: To keep resources isolated, create a dedicated namespace for this tutorial:

kubectl create ns demo
namespace/demo created

Deploying the PostgreSQL Replication Cluster

KubeBlocks uses a declarative approach for managing PostgreSQL clusters. Below is an example configuration for deploying a PostgreSQL cluster with 2 nodes (1 primary, 1 replicas) and custom password generation policy.

apiVersion: apps.kubeblocks.io/v1
kind: Cluster
metadata:
  name: pg-cluster
  namespace: demo
spec:
  terminationPolicy: Delete
  clusterDef: postgresql
  topology: replication
  componentSpecs:
    - name: postgresql
      serviceVersion: 16.4.0
      disableExporter: true
      replicas: 2
      systemAccounts:
        - name: postgres
          passwordConfig:
            length: 20           # Password length: 20 characters
            numDigits: 4         # At least 4 digits
            numSymbols: 2        # At least 2 symbols
            letterCase: MixedCases # Uppercase and lowercase letters
            symbolCharacters: '!' # set the allowed symbols when generating password
      resources:
        limits:
          cpu: "0.5"
          memory: "0.5Gi"
        requests:
          cpu: "0.5"
          memory: "0.5Gi"
      volumeClaimTemplates:
        - name: data
          spec:
            accessModes:
              - ReadWriteOnce
            resources:
              requests:
                storage: 20Gi

Explanation of Key Fields

• systemAccounts: Overrides system accounts defined in the referenced ComponentDefinition.
• passwordConfig: Customizes the password generation policy for the postgres user.
• symbolCharacters: Sets the allowed symbols when generating password.

To get the of accounts:

kubectl get cmpd postgresql-16-1.0.0         -oyaml | yq '.spec.systemAccounts[].name'

Expected Output:

postgres
kbadmin
...

Verifying the Deployment

Monitor the cluster status until it transitions to the Running state:

kubectl get cluster pg-cluster -n demo -w

Expected Output:

NAME         CLUSTER-DEFINITION   TERMINATION-POLICY   STATUS     AGE
pg-cluster   postgresql           Delete               Creating   50s
pg-cluster   postgresql           Delete               Running    4m2s

Once the cluster status becomes Running, your PostgreSQL cluster is ready for use.

Connecting to the PostgreSQL Cluster

KubeBlocks automatically creates a secret containing the PostgreSQL postgres credentials. Retrieve the credentials with the following commands:

PASSWORD=$(kubectl get secrets -n demo pg-cluster-postgresql-account-postgres -o jsonpath='{.data.password}' | base64 -d)

To connect to the cluster's primary node, use the PostgreSQL client with the custom password:

kubectl exec -it -n demo pg-cluster-postgresql-0 -c postgresql -- env PGUSER=postgres PGPASSWORD=$PASSWORD psql

Cleanup

To remove all created resources, delete the PostgreSQL cluster along with its namespace:

kubectl delete cluster pg-cluster -n demo
kubectl delete ns demo

Summary

In this guide, you:

• Deployed a PostgreSQL cluster in KubeBlocks with a custom password generation policy.
• Verified the deployment and connected to the cluster's primary node using the PostgreSQL client.