Error running PostgreSQL Deployment in Kubernetes: "No such file or directory" for data directory

Question

I am trying to deploy a PostgreSQL database using Kubernetes and encountered an error related to the data directory. Below is my YAML configuration for the Deployment:

apiVersion: apps/v1
kind: Deployment
metadata:
  name: db
spec:
  replicas: 1
  selector:
    matchLabels:
      app: db
  template:
    metadata:
      labels:
        type: deployment
        app: db
    spec:
      affinity:
        nodeAffinity:
          requiredDuringSchedulingIgnoredDuringExecution:
            nodeSelectorTerms:
              - matchExpressions:
                  - key: affinity-type
                    operator: In
                    values:
                      - postgres
      tolerations:
        - key: "key"
          value: "database"
          operator: "Equal"
          effect: "NoSchedule"
      volumes:
        - name: db-nfs-pvc
          persistentVolumeClaim:
            claimName: db-nfs-pvc
        - name: init-volume
          configMap:
            name: db-init
        - name: db-hba-conf
          configMap:
            name: hba-init
        - name: db-postgresql-conf
          configMap:
            name: postgresql-conf-init
      containers:
        - name: db
          image: postgres:14-bullseye
          imagePullPolicy: IfNotPresent
          ports:
            - containerPort: 5432
          envFrom:
            - secretRef:
                name: db
          volumeMounts:
            - name: db-nfs-pvc
              mountPath: /var/lib/postgresql/data
              subPath: pgdata
            - name: init-volume
              mountPath: /docker-entrypoint-initdb.d/
            - name: db-postgresql-conf
              mountPath: /var/lib/postgresql/data/postgresql.conf
              subPath: postgresql.conf
            - name: db-hba-conf
              mountPath: /var/lib/postgresql/data/pg_hba.conf
              subPath: pg_hba.conf
          command:
            - "postgres"
            - "-c"
            - "config_file=/var/lib/postgresql/data/postgresql.conf"
            - "-c"
            - "hba_file=/var/lib/postgresql/data/pg_hba.conf"

POSTGRESQL_ENV:

POSTGRES_USER=admin
POSTGRES_PASSWORD=password
PGDATA=/var/lib/postgresql/data/pgdata

Issue: Upon deploying the PostgreSQL database using the above configuration, the pod fails to start, and the logs show the following error:

postgres: could not access directory "/var/lib/postgresql/data/pgdata": No such file or directory
Run initdb or pg_basebackup to initialize a PostgreSQL data directory.

kubectl describe pod:

0/11 nodes are available: pod has unbound immediate PersistentVolumeClaims. preemption: 0/11 nodes are available: 11 No preemption victims found for incoming pod.

Additional Information:

• I have verified that the PersistentVolumeClaim db-nfs-pvc is bound and available.
• I have included the environment variables POSTGRES_USER, POSTGRES_PASSWORD, and PGDATA to specify the PostgreSQL user, password, and data directory path.