Linux answer to Windows Active Directory?
I've been a desktop Linux user since you had to boot the A1 floppy disk but haven't really done any network administration stuff with it. Just plain old desktop installs. And once upon a time I was a network administrator, but that was all on NT4 and 2000 Server with 2000 Pro and XP desktops. Did I mention it's been a while? Anyways what I'd like to set up is something like Windows Domains or AD, but on Linux. I know this has to be a really common use case. I now own a small business, we have four part-time employees and three desktop computers, so it's not a huge org but I'd like to set it up like one. Hopefully someday we won't be so small.
My goal is to have user auth and file storage on a local server, /home mounted on NFS or whatever the best way to do that is nowadays, and...RADIUS? I don't even know what's out there. Is there such a thing as Linux Domains? I'm using Kubuntu pretty much across the board except my workstation which is on OpenSuSE Tumbleweed, if that makes any difference. The server box is an actual Dell server, albeit a fairly old one, that also currently has Kubuntu on it. I'd prefer to avoid Samba and other Wiindows protocols just on general principles but if I gotta I gotta. Ideally it would be pretty easy to scale up with a single central server for authentication and file servers at each store location (target about 8, eventually).
What's the best way to approach this?