Configuring NFS for use with Ranhcer

I am running a single host with rancher and all containers on the same host.
Now I run into high loads and thinking about adding another host.

However I have statefull container (databases) and stateless container (applications which speak with the databases)

All my containers have mounted volumes. So my plan is to add an NFS storage driver to rancher.

I am running in a cloud environment, I do not physically own the network or the servers. So I am a little bit curious how to secure a NFS-Server in this environment.

Until now I only used them in a LAN, never in a WAN. How would authentication work and what services do I need in order to secure everything. What does Rancher bring out of the box to establish persistent transferable volumes? How about Rancher 2 / Kubernets?