[blucaz]

D-Bus will never be removed. Varlink was added because the kernel refused to provide usable IPC primitives, like other OSes have, so a brokered IPC is simply unfeasible in early userspace. So now we have two IPCs that will work in parallel, forever, because such is life on Linux.

[jauntywundrkind]

It would be hella interesting to me to see internal uses of dbus vs varlink. I don't think the proposition was that dbus is removed or goes away (it's the standard FreeDesktop IPC after all), but the scuttlebutt I ran into was that there was an intent to be able to run without it. That a large part of the systemd mono-repo ought be able to do what it does without it, and especially critical & especially especially boot critical systems. It would be interesting to see & weigh over time which parts have support for which IPC, to see if varlink is indeed growing or converging.

You are 100% dead on, btw; thank you for saying! The overwhelming reason for varlink adoption is early boot, where dbus isn't up yet. That's a crucial fact here.