zlacker

>>todsac+(OP)
I would like a comparison with runit, which is a very minimal but almost full-fledged init system. I see many similarities: control directories, no declarative dependencies, a similar set of scripts, the same approach to logging. The page mentions runit in passing, and even suggests using the chpst utility from it.

One contrasting feature is parametrized services: several similar processes (like agetty) can be controlled by one service directory; I find it neat.

Another difference is the ability to initiate reboot or shutdown as an action of the same binary (nitroctl).

Also, it's a single binary; runit has several.

>>nine_k+0k
Last year I decommed our last couple of servers that ran processes configured using runit. It was a sad day. I first learned to write runit services probably about 15 years ago and it was very cool and very understandable and I kind of just thought that's how services worked on linux.

Then I left Linux for about 5 years and, by the time I got back, Systemd had taken over. I heard a few bad things about it, but eventually learned to recognise that so many of those arguments were in such bad faith that I don't even know what the real ones are any more. Currently I run a couple of services on Pi Zeros streaming camera and temperature data from the vivarium of our bearded dragon, and it was so very easy to set them up using systemd. And I could use it to run emacsd on my main OpenSuse desktop. And a google-drive Fuse solution on my work laptop. "having something standard is good, actually", I guess.

>>J_McQu+nX
The backlash against systemd was twofold. On one hand, when released and thrust upon distros via Gnome, it was quite rough around the edges, which caused both real problems and just understandable irritation. Fifteen years after, the kinks are ironed out, but it was sort of a long time. (Btrfs, released at about the same time, took even longer to stop being imprudent to use in production.)

On the other hand, systemd replaces Unix (sort of like Hurd, but differently). It grabs system init, logging, authentication, DNS, session management, cron, daemon monitoring, socket activation, running containers, etc. In an ideal Red Hat world, I suppose, a bare-metal box should contain a kernel, systemd, podman, IP tools, and maybe sshd and busybox. This is a very anti-Unix, mainframe-like approach, but for a big consulting firm, like Red Hat / IBM, it is very attractive.

>>nine_k+Ha1
No, systemd absolutely does not replace Unix.

Systemd-the-project and systemd-the-service-manager (“init”) are two different things. The former is a project with numerous components (e.g. resolved) that actually _are_ rather modular; they usually require systemd-the-service-manager, but you (or your distro) can generally pick and choose the components you want.

The service manager does indeed require some components to be gobbled up (udev comes to mind). But subsuming other subsystems shouldn’t be so anathema; the systemd people didn’t just think that “the one” thing of the Unix philosophy wasn’t being done well. Rather, the idea is that is was the wrong thing, i.e. classic Unix init was a tool operating at the wrong layer of abstraction. And in their eyes, a modern system needs a richer set of userspace primitives. So they made engineering decisions in pursuit of that goal.