> Why would a server use a different init system than a desktop or embedded device?
The futzing around with resolv.conf(5) for one.
I take to setting the immutable flag on the file given all the shenanigans that "dynamic" elements of desktop-y system software does with the file when I want the thing to never change after I install the server. (If I do need to change something (which is almost never) I'll remove/re-add the flag via Anisble's file:attr.)
Of course nowadays "init system" now also means "network settings" for some reason, and I have often have to fight between system-networkd and NetworkManager on some distros: I was very happy with interfaces(5), also because once I set the thing on install on a server, I hardly have to change it and the dynamic-y stuff is an anti-feature.
SystemD as init replacement is "fine"; SystemD as kitchen-sink-of-the-server-with-everything-tightly-coupled can get annoying.
> Why would a server use a different init system than a desktop or embedded device?
The server and desktop have a lot more disk+RAM+CPU than the embedded device, to the point that running systemd on the low end of "just enough to run Linux" would be a pain.
Outside embedded, though, it probably works uniformly enough.
Why compare a "full-featured", do-everything OS like Ubuntu with something pre-systemd when you're concerned about memory consumption?
I just checked a random debian 12 system (with systemd) running a bunch of services at home, and here's what I see:
$ free -m
total used free shared buff/cache available
Mem: 3791 320 2235 1 1313 3471
Swap: 99 0 99
Seems like usage is pretty much on par with your expectation. The largest consumers are systemd-journal which is storing logs in RAM, and filebeat which is relatively wasteful w/ memory. systemd itself (without the journal buffer log) consumes maybe 20-30 MB.
On one (coreelec) systemd has 7M of resident data, of which 5.5M are shared libraries; by comparison, the numbers for sshd are respectively 6M and 3.5M.
On an OpenWRT machine without systemd (it's using procd) there are 700k of resident data. So the "cost" of systemd seems to be ~5M. Certainly I wouldn't run systemd on an old router with 16MB of RAM, but the cost is two orders of magnitude less than 1G-300M.
Until you need to actually dive deep into complicated scenarios. In sysv init you were on your own, which could be for better or for worse. In the world of systemd you either do as LP says or you do not at all.
Why can't you just call a sysv init script (or other customised script) from a systemd service? I did this just the other day when I wanted to delay starting of docker/nfs-kernel-server until a DRBD disk was mounted. I found problems with doing it just using the standard systemd methods to delay start as having a prerequisite meant that the service would fail to start and not attempt to restart. My solution was to put together a script that would check for the existence of a file (located on the mounted DRBD disk) and sleep for 5 seconds if it didn't exist and as soon as the file did exist, it'd call the systemctl command to start docker etc.
If this is a hard job for you well maybe get another career mate. Especially now with LLMs.
The thing to me is that services sometimes do have cause to be more complex, or more secure, or to be better managed in various ways. Over time we might find (for ex) oh actually waiting for this other service to be up and available first helps.
And if you went to run a service in the past, you never know what you are going to get. Each service that came with (for ex) Debian was it's own thing. Many forked off from one template or a other. But often forked long ago, with their own idiosyncratic threads woven in over time. Complexity emerged, and it wasn't contained, and it crrtainly wasn't normalized complexity across services: there would be dozens of services each one requiring careful staring at an init script to understand, with slightly different operational characteristics and nuance.
I find the complaints about systemd being complex almost always look at the problem in isolation. "I just want to run my (3 line) service, but I don't want to have to learn how systemd works & manages unit: this is complex!". But it ignores the sprawl of what's implied: that everyone else was out there doing whatever, and that you stumble in blind to all manners of bespoke homegrown complexity.
Systemd offers a gradient of complexity, that begins with extremely simple (but still offering impressive management and oversight), and that lets services wade into more complexity as they need. I think it is absolutely humbling and to some people an affront to see man pages with so so so many options, that it's natural to say: I don't need this, this is complex. But given how easy it is, how much great ability to see the state of the world we get that SysV never offered, given the standard shared culture tools and means, and given the divergent evolutionary chaos of everyone muddling through init scripts themselves, systemd feels vastly more contained, learnable, useful, concise, and less complex than the nightmares of old. And it has simple starting points, as shown at the top, that you can add onto and embelish onwards as you find cause to move further along the gradient of complexity, and you can do so in a simple way.
It's also incredibly awesome how many amazing tools for limiting process access, for sandboxing and securing services systemd has. The security wins can be enormous.
> Because last time I wrote systemd units it looked like a job
Last, an LLM will be able to help you with systemd, since it is common knowledge with common practice. If you really dislike having to learn anything.
Yeah, I've been using Claude and Codex to create bespoke systemd services for my random tools and automation stuff and have been really impressed by how easy it is and how rock solid they are once setup. It's really nice not living in constant terror that a reboot, network connectivity loss or gentle breeze will cause my duct taped scripts to collapse under their own weight.
I dunno man. The past was a shit show & you seem extremely resistant to trying at all.
I struggle to figure out what it is that the systemd haters club actually struggles with, what is actually the hard parts. I do in fact sometimes use a 3 line .service file and it works fine. It feels like there is a radically conservative anti progress anti learning anti trying force that is extremely vocal that shows up all the time everywhere in any thread, to protest against doing anything or learning anything. I really really am so eager to find the learnable lessons, to find the hard spots, but it's almost entirely the same low grade discursive trashing with no constructive or informative input.
It feels like you use emotional warfare rather than reason. The culture I am from is powerless against that if that's all you bring but I also feel no respect for a culture that is so unable to equivocate what the fuck it's problems actually are. Imo we all need a social defense against complaints that are wildly vacuous & unspecific. Imo you are not meeting any baselines for taking your whinges seriously.
Because last time I wrote systemd units it looked like a job.
Also, way over complex for anything but a multi user multi service server. The kind you're paid to maintain.