Systemd and containers

Recent proponents of merging the root filesystem with /usr initially thought this too, but came to realise that unifying into /usr made more sense than unifying into / - the lib, libexec, share, bin, sbin directories have more in common with each other than with anything else that has traditionally been at the top level.

/usr is not meant to change, ever, except during OS upgrades/package installations (and perhaps installations to /usr/local if you use that); so it can normally be mounted read-only, and if you're using something like OSTree, all of /usr should change atomically as a single unit. The "merged /usr" model does support a separate /usr filesystem, if the initramfs mounts it.

https://wiki.freedesktop.org/www/Software/systemd/TheCase... mentions some other possibilities, like a shared /usr between machines that have the same architecture and package-set (admittedly this makes more sense on OSs like Fedora, where services are normally installed but disabled by default, than on Debian derivatives, where unwanted services are normally not installed).

... Nneeeggh! I don't really want all those directories cluttering up my /.

I don't want /bin, I don't want /sbin, I don't want /lib, I don't want /share, I don't want /local, and I certainly don't want /include.

It's kind of a shame that sysfs took over /sys otherwise I'd really push for just changing /usr's name to /sys.
But heck, people can't even agree on what /usr means today -- I keep getting told it's Unix System Resources, but to me it's always been the /usEr/ directory.

"I do not at all have the mind of a bully... in my mind bullies are intolerant of contrary opinion, domineering and rather cowardly. I would hope that none of those terms could be fairly used in describing me." -- Conrad Black

But that would be one of those changes that breaks the world because too many things rely on /usr/bin/<something>.

Thankfully on a lot of modern systems, /bin, /sbin, and /lib are just links to their /usr counterparts. One day they'll dissipate.

Eventually the old ash/bash/perl scripts will get replaced by python3, rust, and go by the distros. Maybe even Swift if it really takes off. I'm kind of skeptical about that one. Coreutils installations will start to be rare as whatever default dynamic language on the installation medium (python3) handles doing all the unixy regexes and transforms without shelling out of process...

X will go back to being an immediate-mode drawing protocol and DRI will be a laughable thing of the past once the wayland ecosystem solidifies. Most of the application toolkits have already supported it for quite a while; then xwayland will handle loading the required xorg components when necessary, like when I want to play a good old fashioned game of xevil. Once enough time passes, xorg won't even be a default installed component anymore and it'll be like "whaaat, I have to go get xorg to run this? Pffft! I'm not going through that hassle, googleing for a native rebuild..." kinda like xQuartz on a mac...

pixman and glamor will keep older fixed function graphics adapters reasonably operational, all the way back to the good ol' ATI mach64 and matrox G200w (Darn you, integrated server KVM devices!) and various framebuffer devices, including spitting SPI out to a 320x240 touchscreen on a Pi's GPIO header.

"I always keep a firewall between my own travails and my perception of public-policy issues; otherwise I would retain no credibility as a commentator." -- Conrad Black

The internet is changing. Unix is changing. If you're not cool with that; Slackware and Linux From Scratch can always use the help! (Although LFS has a systemd version which may become standard...)

Lennart's swiped the three most useful apple services, mdns/bonjour/avahi, coreaudio/pulseaudio, launchd/systemd, ripped them to chunks, and had a go at putting together a lego tower with the results.

"There are some people whose opinion I value and respect and it would be very bothersome if I forfeited their respect. But the general public? I'm not preoccupied with the opinions of others." -- Conrad Black

I've played with that lego tower, and honestly, I like it a lot better than the old duplo sysvinit set.
Some of it gets a little strange, like finding a block of lego technics pieces in with your classics.

"Containers in my init system? It's more common than you think." -- Adapted internet meme

Ubuntu's wiki actually put together a great little mapping page between the upstart features and the systemd features:
https://wiki.ubuntu.com/SystemdForUpstartUsers
It's short, it's sweet, and it's mostly useful for users of other distros as well just to get a quick cheat sheet on systemd.