Simple Cluster

1. creating postgresql cluster

   kubectl apply -f cluster.yaml
   

2. postgresql get cluster will show the master IP

   zufar.dhiyaullhaq@Zufar-Dhiyaulhaq github % k get cluster
   NAME              AGE    INSTANCES   READY   STATUS                     PRIMARY
   echo-postgresql   7d6h   4           4       Cluster in healthy state   echo-postgresql-1
   

3. pod is created

   zufar.dhiyaullhaq@Zufar-Dhiyaulhaq github % k get pod
   NAME                                   READY   STATUS    RESTARTS   AGE
   cnpg-cloudnative-pg-7bf9fd4554-52tqk   1/1     Running   0          3d17h
   echo-postgresql-1                      1/1     Running   0          7d6h
   echo-postgresql-2                      1/1     Running   0          3d6h
   echo-postgresql-3                      1/1     Running   0          7d5h
   echo-postgresql-4                      1/1     Running   0          7d5h
   

4. service is created

   zufar.dhiyaullhaq@Zufar-Dhiyaulhaq github % k get svc
   NAME                   TYPE        CLUSTER-IP      EXTERNAL-IP   PORT(S)    AGE
   cnpg-webhook-service   ClusterIP   172.16.2.65     <none>        443/TCP    7d6h
   echo-postgresql-r      ClusterIP   172.16.10.189   <none>        5432/TCP   7d6h
   echo-postgresql-ro     ClusterIP   172.16.6.253    <none>        5432/TCP   7d6h
   echo-postgresql-rw     ClusterIP   172.16.7.245    <none>        5432/TCP   7d6h
   

5. there is secret created for this postgresql

   zufar.dhiyaullhaq@Zufar-Dhiyaulhaq github % k get secret echo-postgresql-app -oyaml
   apiVersion: v1
   data:
     dbname: YXBw
     host: ZWNoby1wb3N0Z3Jlc3FsLXJ3
     jdbc-uri: xxx
     password: yyy
     pgpass: zzz
     port: aaa
     uri: bbb
     user: YXBw
     username: YXBw
   

6. by default, it's create database "app" and user "app" if it's not defined.
7. create deployment

   kubectl apply -f deployment.yaml
   kubectl get pod
   

8. port forward service & test curl

   kubectl port-forward svc/echo-postgresql 8080:8080
   while true; do curl http://localhost:8080/postgresql/test; sleep 0.5; done
   

9. port forward database & check table

   kubectl port-forward svc/echo-postgresql-rw -n cnpg-system 5432:5432
   
   export PG_DB=$(kubectl get secret echo-postgresql-app -o jsonpath='{.data.dbname}' | base64 -d)
   export PG_USER=$(kubectl get secret echo-postgresql-app -o jsonpath='{.data.user}' | base64 -d)
   export PG_PASSWORD=$(kubectl get secret echo-postgresql-app -o jsonpath='{.data.password}' | base64 -d)
   
   psql -h 127.0.0.1 -p 5432 -d app -U app
   
   zufar.dhiyaullhaq@MacBookPro 1-simple-cluster % psql -h 127.0.0.1 -p 5432 -d app -U app
   Password for user app: 
   psql (14.18 (Homebrew), server 17.5 (Debian 17.5-1.pgdg110+1))
   WARNING: psql major version 14, server major version 17.
            Some psql features might not work.
   SSL connection (protocol: TLSv1.3, cipher: TLS_AES_256_GCM_SHA384, bits: 256, compression: off)
   Type "help" for help.
   
   app=> \dt
          List of relations
    Schema | Name  | Type  | Owner 
   --------+-------+-------+-------
    public | echos | table | app
   (1 row)
   
   app=> select * from echos;
             created_at           |          updated_at           | deleted_at |                  id                  | echo 
   -------------------------------+-------------------------------+------------+--------------------------------------+------
    2025-07-04 15:01:50.560357+00 | 2025-07-04 15:01:50.554699+00 |            | b538474e-1106-42f3-a8c6-345449606158 | test
    2025-07-04 15:01:51.401685+00 | 2025-07-04 15:01:51.399392+00 |            | c72a1b22-4660-4cd8-9c75-808335729df5 | test
   

Manifests

cluster.yaml

apiVersion: postgresql.cnpg.io/v1
kind: Cluster
metadata:
  name: echo-postgresql
  namespace: cnpg-system
spec:
  instances: 4
  storage:
    size: 1Gi

deployment.yaml

apiVersion: apps/v1
kind: Deployment
metadata:
  name: echo-postgresql
  namespace: cnpg-system
  labels:
    app: echo-postgresql
spec:
  replicas: 1
  selector:
    matchLabels:
      app: echo-postgresql
  template:
    metadata:
      labels:
        app: echo-postgresql
    spec:
      containers:
      - name: echo-postgresql
        image: ghcr.io/zufardhiyaulhaq/echo-postgresql:v1.0.0
        ports:
        - containerPort: 8080
          name: http
        env:
        - name: HTTP_PORT
          value: "8080"
        - name: POSTGRESQL_HOST
          value: "echo-postgresql-rw.cnpg-system.svc.cluster.local"
        - name: POSTGRESQL_PORT
          value: "5432"
        - name: POSTGRESQL_DATABASE
          valueFrom:
            secretKeyRef:
              name: echo-postgresql-app
              key: dbname
        - name: POSTGRESQL_USER
          valueFrom:
            secretKeyRef:
              name: echo-postgresql-app
              key: user
        - name: POSTGRESQL_PASSWORD
          valueFrom:
            secretKeyRef:
              name: echo-postgresql-app
              key: password
        resources:
          requests:
            cpu: "100m"
            memory: "128Mi"
          limits:
            cpu: "500m"
            memory: "512Mi"
---
apiVersion: v1
kind: Service
metadata:
  name: echo-postgresql
  namespace: cnpg-system
spec:
  selector:
    app: echo-postgresql
  ports:
    - protocol: TCP
      port: 8080
      targetPort: http
  type: ClusterIP

https://cloudnative-pg.io/documentation/1.26/quickstart/ https://cloudnative-pg.io/documentation/1.26/applications/