Re: systemd manages cgroups, among other things

Le 03-03-2024, Lawrence D'Oliveiro <ldo@nz.invalid> a écrit :

On Sun, 03 Mar 2024 10:18:50 +0000, Farley Flud wrote:
>

What use are cgroups on a standalone, desktop workstation?

It's a pity I can't see the original message. At least, I see this funny
question. As you didn't answered it, I will, because it's important to
answer his mistakes. I don't disagree with him because it's not a matter
of taste. It's a matter of knowledge, which he clearly lacks.
Let's be clear: if he doesn't want to use modern stuff, it's a question
of choice. To deduce from it, it's useless for a desktop workstation is
just plain wrong. So, it must be corrected with arguments. And there are
many.
First things first. You have a process which will takes time. There is
no hurry, so it will run in the background and you want to keep using
your computer during this time. I mean, not like FR/DG/LP/FF/whatever
who just stare at his useless computer when he tries to compile
something. So at that moment, you want to force this process to let you
some ressources to let you use your computer. It's the time the cgroups
are useful. You find your compiler takes too many CPU? => use the
cgroups. You find Firefox takes too many memory? => cgroups.
Second, the containers like podman or docker are relying heavily on
cgroups. As he probably believes containers are useless on desktop
workstations, I have to prevent his objection.
A container can be used on a personal computer to be sure it will be run
exactly in the same way as somewhere else. For example, I compile my
LaTeX documents with the same container on my computer and on the gitlab
instance which is hosting my files. Like that, I'm sure the document on
my computer is exactly the same as the one downloaded by others. The containers are used by immutable distros (not Guix and NixOS but
silverblue). The purpose is to isolate the programs/libraries used by
the end user from those used by the system. Like that, one can use
whatever one want without risk of breaking one's system. And one can
upgrade one's system without risk to have issues to break one's
applications.
Another use is if you want to try something, like a new version of an
application before upgrading it. Or to have two versions of the same
application for different purposes at the same time.
So, yes, cgroups can be useful for normal usage of a personal
desktop workstation. Whatever he says.
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