JG-mirror/LXC/NAS

On LXC Create User Group

groupadd -g 10000 lxc_shares

Optional: Add Other Users to Group (e.g., Jellyfin, Plex)

usermod -aG lxc_shares USERNAME

On Proxmox Host

Create a folder to mount the NAS

mkdir -p /mnt/lxc_shares/nas_rwx

Add NAS CIFS share to /etc/fstab

Replace //NAS-IP-ADDRESS with your NAS IP Replace Username and Passwords

{ echo '' ; echo '# Mount CIFS share on demand with rwx permissions for use in LXCs ' ; echo '//NAS-IP-ADDRESS/nas/ /mnt/lxc_shares/nas_rwx cifs _netdev,x-systemd.automount,noatime,uid=100000,gid=110000,dir_mode=0770,file_mode=0770,user=smb_username,pass=smb_password 0 0' ; } | tee -a /etc/fstab

Mount the NAS to the Proxmox Host

mount /mnt/lxc_shares/nas_rwx

Add Bind Mount of the Share to the LXC Config

Be sure to change the LXC_ID

You can mount it in the LXC with read+write+execute (rwx) permissions.
{ echo 'mp0: /mnt/lxc_shares/nas_rwx/,mp=/mnt/nas' ; } | tee -a /etc/pve/lxc/LXC_ID.conf

You can also mount it in the LXC with read-only (ro) permissions.
{ echo 'mp0: /mnt/lxc_shares/nas_rwx/,mp=/mnt/nas,ro=1' ; } | tee -a /etc/pve/lxc/LXC_ID.conf

Thanks to https://forum.proxmox.com/members/thehellsite.88343/ for tips