In case you want to know even more stuff Systemd can do, here's a
handy list over at Suckless.
Also always interesting to read this blog post features on Freebsd.org on the press releases from 2017 by Synergy Sky, named:
"Why we did build our solution on top of FreeBSD?" So in a year where Systemd has already been around for quite a while, and also in their Linux distribution of choice CentOS.
Money quote: "One major issue we experienced was that Systemd managed to crash the whole dbus-systemd connection if our software took too much memory, leaving the system in unstable state, with reboot as only option (I don’t think we can blame CentOS directly for that, however pulling in such premature technology into a proclaimed stable platform, makes no sense at all!!). We had some other minor issues as well which is probably weeded out in the latest versions of CentOS (and not worth mentioning)."
Theodore T'so, creator of ext2/3/4 file systems had also problems to tinker it in a way he wanted it to behave. It was a really interesting read back then, sadly lost with the begone Google+.
And Bruce Perens, who was within Debian, was of this opinion in 2014:
"Here's another issue brought to a head by systemd. There's a conflict for anyone with a job like being on the TC for an obvious reason: Systemd achieves some powerful and important goals for Linux systems. And at the same time Systemd doesn't play well with others (especially other init systems) and is badly in need of being broken up into separate projects.
Debian was able to allow individual developers to make decisions
because it's modular. Systemd isn't modular enough to fit the Debian paradigm, at least at present. And the way it's been pushed upon the entire community is deplorable.
It's time to put on the brakes. We need to break systemd up into separate projects, resolve the issues that cause the largest objections to it, and make sure it plays with others (again, including other init systems). Oh, and pushing back on the team that pushed it upon us is unfortunately necessary.
Until those issues are handled, Debian (and other sensible distributions) should not be based upon systemd."
And it gives you fun stuff like this now and then, crashing a whole machine by sending a specially designed dbus message to it:
https://seclists.org/oss-sec/2019/q1/140
And even Linus Torvalds dislikes the systemd developer's attitude, because systemd uses some kernel stuff in a way it was not meant to be, e.g. dmesg buffter. So people are filing bugs against the kernel, not systemsd. When then the kernel developers filed these bugs against systemd, they were pretty much and fast closed.
Interesing mail from 2017 on same patch: "
So I see many different approaches (that could be combined: I like
combining (a) and (c), for example), and absolutely none of them
involve the random "take some values from init".
And yes, a large part of this may be that I no longer feel like I can
trust "init" to do the sane thing. You all presumably know why."
Which basically is him saying that the he thinks that the most popular init thingie on his kernel sucks. And he's gruntled about when he's got to change his kernel do to the inability/unwillingness of the systemd developers to correct their mistakes.