Kubernetes NFS persistent volumes permission denied

A simple way is to get to the nfs storage, and chmod 777, or chown with the user id in your volume-test container

If you set the proper securityContext for the pod configuration you can make sure the volume is mounted with proper permissions.

Example:

apiVersion: v1
kind: Pod
metadata:
  name: demo
spec:
  securityContext:
    fsGroup: 2000 
  volumes:
    - name: task-pv-test-storage
      persistentVolumeClaim:
        claimName: task-pv-test-claim
  containers:
  - name: demo
    image: example-image
    volumeMounts:
    - name: task-pv-test-storage
      mountPath: /data/demo

In the above example the storage will be mounted at /data/demo with 2000 group id, which is set by fsGroup. By setting the fsGroup all processes of the container will also be part of the supplementary group ID 2000, thus you should have access to the mounted files.

You can read more about pod security context here: https://kubernetes.io/docs/tasks/configure-pod-container/security-context/

Thanks to 白栋天 for the tip. For instance, if the pod securityContext is set to:

securityContext:
  runAsUser: 1000
  fsGroup: 1000

you would ssh to the NFS host and run

chown 1000:1000 -R /some/nfs/path

If you do not know the user:group or many pods will mount it, you can run

chmod 777 -R /some/nfs/path