Postgresql data is seemingly not persisted

[nixonjoshua98]

Hi, the issue I have currently is that /var/lib/postgresql is not being persisted across pod restarts but an added test file at /var/lib/postgresql/test is persisted between node switches and pod restarts and I dont understand why.

postgresql.deployment.yaml

apiVersion: apps/v1
kind: Deployment
metadata:
  name: postgresql
spec:
  selector:
    matchLabels:
      app: postgresql
  template:
    metadata:
      labels:
        app: postgresql
    spec:
      containers:
        - name: postgresql
          image: postgres:16
          ports:
            - containerPort: 5432
          env:
            - name: POSTGRES_PASSWORD
              valueFrom:
                configMapKeyRef:
                  name: postgresql-config
                  key: POSTGRES_PASSWORD
          volumeMounts:
            - name: postgresql-data
              mountPath: /var/lib/postgresql
      volumes:
        - name: postgresql-data
          persistentVolumeClaim:
            claimName: postgresql-pvc

postgresql-pvc.yaml

apiVersion: v1
kind: PersistentVolumeClaim
metadata:
  name: postgresql-pvc
  labels:
    app: postgresql
spec:
  accessModes:
    - ReadWriteOnce
  resources:
    requests:
      storage: 10Gi

postgresql-service.yaml

apiVersion: v1
kind: Service
metadata:
  name: postgresql
  labels:
    app: postgresql
spec:
  clusterIP: None
  selector:
    app: postgresql
  ports:
    - port: 5432

Adding data to the database then restarting the pod causes all the changes to be lost, but adding a test file into the volume seems to persist. I can't seem to figure out why

---

[nixonjoshua98]

I have to set a subPath on the mount, and mount directly onto /data

volumeMounts:
   - name: postgresql-data
     mountPath: /var/lib/postgresql/data
     subPath: postgresql