I am in the process of setting up a NFS server on my K8S cluster. I want it to act as a NFS server for external entities i.e. client will be from outside the K8S cluster such as VMs.

The port requirements for the Docker image are :

==================================================================
      SERVER STARTUP COMPLETE
==================================================================
----> list of enabled NFS protocol versions: 4.2, 4.1, 4
----> list of container exports:
---->   /exports *(rw,no_subtree_check)
----> list of container ports that should be exposed:
---->   111 (TCP and UDP)
---->   2049 (TCP and UDP)
---->   32765 (TCP and UDP)
---->   32767 (TCP and UDP)

So I have created a Debian Stretch docker image. When I run it using docker run, I can successfully expose /exports and mount it from other systems.

docker run -v /data:/exports -v /tmp/exports.txt:/etc/exports:ro \
--cap-add SYS_ADMIN -p 2049:2049 -p 111:111 -p 32765:32765 \
-p 32767:32767 8113b6abeac

The above command spins up my docker container and when I do

mount.nfs4 <DOKCER_HOST_IP>:/exports /mount/

from another VM, I can successfully mount the volume.

So everything up until here is A OK!

Now the task is to deploy this in K8S.

My stateful-set definition is:

kind: StatefulSet
apiVersion: apps/v1
metadata:
  name: nfs-provisioner
spec:
  selector:
    matchLabels:
      app: nfs-provisioner
  serviceName: "nfs-provisioner"
  replicas: 1
  template:
    metadata:
      labels:
        app: nfs-provisioner
    spec:
      serviceAccount: nfs-provisioner
      terminationGracePeriodSeconds: 10
      imagePullSecrets:
      - name: artifactory
      containers:
        - name: nfs-provisioner
          image: repository.hybris.com:5005/test/nfs/nfs-server:1.2
          ports:
            - name: nfs
              containerPort: 2049
            - name: mountd
              containerPort: 20048
            - name: rpcbind
              containerPort: 111
            - name: rpcbind-udp
              containerPort: 111
              protocol: UDP
            - name: filenet
              containerPort: 32767
            - name: filenet-udp
              containerPort: 32767
              protocol: UDP
            - name: unknown
              containerPort: 32765
            - name: unknown-udp
              containerPort: 32765
              protocol: UDP
          securityContext:
            privileged: true
          env:
            - name: SERVICE_NAME
              value: nfs-provisioner
            - name: NFS_EXPORT_0
              value: '/exports *(rw,no_subtree_check)'
          imagePullPolicy: "IfNotPresent"
          volumeMounts:
            - name: export-volume
              mountPath: /exports
      volumes:
        - name: export-volume
          hostPath:
            path: /var/tmp

As you can see, I have specified all the ports (both TCP and UDP)

And now to expose this to the outside world and not just inside the cluster, my service.yaml file deceleration is :

kind: Service
apiVersion: v1
metadata:
  name: nfs-provisioner
  labels:
    app: nfs-provisioner
spec:
  type: NodePort
  ports:
    - name: nfs
      port: 2049
    - name: mountd
      port: 20048
    - name: rpcbind
      port: 111
    - name: rpcbind-udp
      port: 111
      protocol: UDP
    - name: filenet
      port: 32767
    - name: filenet-udp
      port: 32767
      protocol: UDP
    - name: unknown
      port: 32765
    - name: unknown-udp
      port: 32765
      protocol: UDP
  selector:
    app: nfs-provisioner

This results in

kubectl get svc
NAME              TYPE        CLUSTER-IP      EXTERNAL-IP   PORT(S)                                                                                                                      AGE
nfs-provisioner   NodePort    10.233.43.135   <none>        2049:30382/TCP,20048:31316/TCP,111:32720/TCP,111:32720/UDP,32767:30173/TCP,32767:30173/UDP,32765:31215/TCP,32765:31215/UDP   32m

Now I try to mount /exports from another node/VM that is external to the K8S cluster.

I've tried

mount.nfs4 <K8S_Node_IP>:/exports /mount/

and I've tried

mount.nfs4 -o port=<NodePort> <K8S_Node_IP>:/exports /mount/

Ive tried each NodePort one at a time. But none of them work. I get the error :

mount.nfs4 -o port=31316 <K8S_Node_IP>:/exports /mount/
mount.nfs4: mount to NFS server '<K8S_Node_IP>:/exports' failed: RPC Error: Unable to receive

I'm unsure as to what might be the issue here. Is it that I need to specify all the nodePorts? If so, how can I do that?