postgres on gke with persistent volume

deployment.yml

apiVersion: extensions/v1beta1
kind: Deployment
metadata:
  labels:
    app: postgres-db
  name: postgres-db
spec:
  replicas: 1
  template:
    metadata:
      labels:
        app: postgres-db
      name: postgres-db
    spec:
      containers:
        - name: postgres-db
          image: postgres:9.6
          imagePullPolicy: Always
          ports:
            - containerPort: 5432
          volumeMounts:
            # Persist our configs in an SQLite DB in here
            - mountPath: /var/lib/postgresql/data
              name: postgres-data
          env:
            - name: PGDATA
              value: "/var/lib/postgresql/data/pgdata"
            - name: DB_PASS
              valueFrom:
                secretKeyRef:
                  name: postgres-secrets
                  key: db_pass
      volumes:
        - name: postgres-data
          gcePersistentDisk:
            pdName: postgres-data
            fsType: ext4

secrets.yml

apiVersion: v1
kind: Secret
metadata:
  name: postgres-secrets
type: Opaque
data:
  db_pass: cGdwYXNz

service.yml

apiVersion: v1
kind: Service
metadata:
  name: postgres-db
  labels:
    app: postgres-db
spec:
  type: NodePort
  ports:
  - port: 5432
    protocol: TCP
  selector:
    app: postgres-db

now what if we had more than one node and need more than one replica?