Yet it seems installing systemd drags dbus and bunch of other dependencies in with it... tomato, potato.

dbus was already there. How do you think udev works?

To be fair, udev communicates over netlink. :)

Only in the future it may use kdbus for some purposes (eg. uploading firmware blobs), but this will only affect internal interfaces.

On the other hand, systemd does not require the D-Bus daemon when you're launching systemctl it as root, the D-Bus daemon is only needed to route the call when used by unprivileged users. When used as root, systemctl connects to the PID1 socket directly and D-Bus is basically just a serialization protocol (and systemd does not depend on libdbus either).

> To be fair, udev communicates over netlink. :)

To be fair, udev communicates with the kernel via netlink. All the userspace notifications are done via dbus. So dbus was already part of the equation whether people realize it or not.

http://blogas.sysadmin.lt/?p=141

Are you sure? IIRC it was HAL that picked the kernel events and converted to D-Bus signals, but it has been deprecated a long time ago.

I gave a cursory glance to the systemd/src/udev files and found no mention of dbus.

I build debian chroots with sysv init. Edit: they have libdbus, but aren't running the dbus daemon, but are running udevd.