[LukeShu]

I'm not sure the author has an understanding of what D-Bus is. The article doesn't really discuss D-Bus at all.

D-Bus is not merged in to systemd. When systemd notices that a service it started is named "dbus", it then registers itself as a D-Bus service; programs (like `systemctl` or `poweroff` then use use D-Bus to send it commands. For comparison, sysvinit accepts commands via a named pipe (`/run/initctl`, or `/dev/initctl` for older versions of sysvinit).

Most services are not made to be D-Bus daemons. A service is only made to be a D-Bus daemon if its unit file says `Type=dbus`; none of the examples in the article say this. You can use D-Bus to ask systemd to start or stop a given service; same as you could use `telinit` to use /run/initctl to tell sysvinit to change the runlevel; this does not make a service started this way a D-Bus service.

The NOTIFY_SOCKET and watchdog functionality that the article discusses... this functionality has nothing to do with D-Bus.

[hauleth]

That section was removed as it was leftover from the early drafts.

[bytelines]

I see! Thank you for taking the time to write that out, much appreciated.