Historically NFS and using one service per server was the usual process. “Builds on” means that the newer processes were developments and improvements to older processes. For example NFS was released in the 1980s and Docker in 2013. Obviously the efficiencies in docker and hyperconverged servers are the reason they have taken over most set ups, but it’s not obvious that software such as docker would have come into existence without the original networking processes.

…which is exactly my point. Using a VM or docker to run the relevant programs and using hard links rather than NFS shares is just a more complicated (but more efficient) setup that follows the same logic. It also has a more complicated network setup for VPN use than running a VPN client on an SBC. That’s why an SBC is the easiest way in to the lifestyle, before graduating to the more complicated yet more powerful setups.

A NAS, an SBC eg a raspberry pi, and NFS shares are the basic setup. Everything else essentially builds on this.