> I also explored the good old automounter[1][2], but it has a lot of the limitations that systemd's does. It does have the advantage of supporting host maps, which gets me a bit closer to what I'm looking for. The unfortunate thing that remains is that this is NFS instead of a modern protocol.

What limitations affect you?

(At home, I have linux running on an HP MicroServer as my NAS, it exports filessytems via NFS. Other machines run autofs with the hosts map, so for example my wife's desktop - and mine for that matter - auto-mounts NFS shares on-demand and she can open any file directly in any application by accessing /net/$hostname/$path).

NFSv4 is pretty modern ...

I believe this should also work for CIFS, if the server-side supports unix extensions (to do user mapping on a single connection), but I haven't had time to try it in the past day in my limited time at home.

> Authentication becomes a problem since the automounter probably can't ask the user for a password, and may not even know which user is requesting the mount.

If you have Kerberos setup, NFSv4 does the right thing ...

If you don't have Kerberos setup, then you're probably ok with just normal NFS user mapping.