I am a Linux user, but I don’t really know how most things work, even after years of casual use on my Main, I just started getting into Devuan and wondered then, what exacly does systemd do that most distros have it? What even is init freedom? And why should I care?
Systemd is the first program that runs once the kernel has started. It’s job is mostly just starting up other processes, and managing those other processes. If you don’t know what systemd is, then you probably shouldn’t care about if you’re using it or not, it’s good software but there are fine alternatives.
What makes systemd particularly interesting is that it is different from historical init systems. Historically these init systems were an unholy mess of shell scripts. This offers maximum flexibility, but limits the functionality of the init system itself. Systemd replaces these shell scripts with simple ini-like service files that allow everything to be declared simply and declaratively, and allows specifying more rich metadata, like dependencies. But it’s different, and some people place a higher value on “how it’s always been” than pragmatism. I personally have zero sympathy for them because throwing out objective progress to hold onto a broken system designed for 1960s computing is just dumb.
Preach.
I had to battle with the fucking initd and upstard before systemd. Those stupid headers of the scripts in /etc/init.d/ we wonderfully undocumented, didn’t have syntax checks, depended on a bunch of other shell scripts that didn’t have any damn comments in them.
systemd was going to happen sooner or later because nobody was going to put up with that bullshit forever.
Those people arguing about “do one thing right” blablabla don’t care about principles, they care about superiority. They want to feel like they’re the minority who can do stuff so that in forums they can be toxic and respond with “RTFM” or “LMGTFY”. They don’t want it easier and more functional, they want it hard so that they can gatekeep.
Like a bunch of Catholics: I experienced pain, so you have to too!
systemd can containerize services! To do that kind of stuff with initd, you’d have to know how create process-, user-, and network namespaces, and a bunch of other stuff.
It’s especially funny because systemd isn’t one program any more than GNU is. It’s a project. systemd-initd handles init. systemd-journald handles journal logs. systemd-resolved handles DNS resolution. Etc. Each systemd daemon has one area of responsibility!