Setting permissions while using NAS volumes for Kubernetes

I am starting on kubernetes and need to migrate some existing docker apps.
We are using internal NAS .

Current Scenario

In Rancher 1.6, I have a docker app running as svc-appuser and NAS drive is exported to the docker host on /nas/data/appname for svc-appuser. So the app can access nas folder without any issues during bootup.Docker-compose looks like below.

version: '2'

services:

  App-server:
    image: ln03:9000/App:1.0.0
    restart: on-failure
    cap_add:
      - SYS_ADMIN
      - DAC_READ_SEARCH
    environment:
      SSL_KEYSTORE_PASSWORD: ${ssl_keystore_password}
      SSL_KEY_ALIAS: ${ssl_key_alias}
    volumes:
      - /nas/data/appname:/opt/appdata

Now in Rancher 2.x, kubernetes, I was reading that we have to create Persistent volume claim (pvc) before deploying application and then use this pvc in yaml file for app deployment.

The docker daemon is run as svc-dockeradmin user. I assume that my Dockerfile to build the image will still be same , i.e

FROM ubuntu:latest
ARG PROXY_HOST
ARG PROXY_PORT
.
.
.
USER svc-appuser
CMD [ "sh", "-c", "/entrypoint.sh; bash"]

My question is how do we get it working in my case.

Until and unless I create the pvc as svc-appuser, there is no way the app can use it after bootup. How do I do that.

I referred Kubernetes-NFS-example and no info there.

PS : The NAS share is already mounted on all hosts for svc-appuser

If you just want to bind-mount a directory on the host into the container, you only need a volume definition and mount as subjects in the deployment, not a PV or PVC.