apiVersion: v1
kind: PersistentVolume
metadata:
  name: postgres-pv
  namespace: webapp-namespace
spec:
  capacity:
    storage: 1Gi
  accessModes:
    - ReadWriteOnce
  hostPath:
    path: "/mnt/data/postgres"
---
apiVersion: v1
kind: PersistentVolumeClaim
metadata:
  name: postgres-pvc
  namespace: webapp-namespace
spec:
  accessModes:
    - ReadWriteOnce
  resources:
    requests:
      storage: 1Gi
---
apiVersion: apps/v1
kind: StatefulSet
metadata:
  name: postgres
  namespace: webapp-namespace
spec:
  serviceName: "postgres"
  replicas: 1
  selector:
    matchLabels:
      app: postgres
  template:
    metadata:
      labels:
        app: postgres
    spec:
      containers:
      - name: postgres
        image: postgres:13
        env:
        - name: POSTGRES_DB
          value: mydatabase
        - name: POSTGRES_USER
          value: myuser
        - name: POSTGRES_PASSWORD
          value: mypassword
        ports:
        - containerPort: 5432
        volumeMounts:
        - name: postgres-storage
          mountPath: /var/lib/postgresql/data
      volumes:
      - name: postgres-storage
        persistentVolumeClaim:
          claimName: postgres-pvc
---
apiVersion: v1
kind: Service
metadata:
  name: postgres
  namespace: webapp-namespace
spec:
  selector:
    app: postgres
  ports:
  - port: 5432