NFS into Containers
I have a fairly cheap Synology system managing my spinning rust storage. Block storage over iSCSI didn't perform very well, so I ended up on NFS. NFS works very well, but unfortunately the support to mount a remote export just isn't there yet. You'll need to mount the NFS share on the host, push the mount into the container as a disk object, and adjust permissions as needed. Here's how I've accomplished this.
NFS SharesMount
mkdir -p /mnt/share
vim /etc/fstab
ip.or.hostname:/volume1/share /mnt/share nfs4 defaults 0 0
mount /mnt/share
Prep Users & Permissions
Personally, I created system users and groups