this post was submitted on 13 Dec 2023
996 points (99.1% liked)
linuxmemes
20463 readers
580 users here now
I use Arch btw
Sister communities:
- LemmyMemes: Memes
- LemmyShitpost: Anything and everything goes.
- RISA: Star Trek memes and shitposts
Community rules
- Follow the site-wide rules and code of conduct
- Be civil
- Post Linux-related content
- No recent reposts
Please report posts and comments that break these rules!
founded 1 year ago
MODERATORS
you are viewing a single comment's thread
view the rest of the comments
view the rest of the comments
systemd daemons are configured via /etc/systemd, and systemd itself lives in /usr/lib/systemd/systemd. How can systemd run or start the configured services without the root disk mounted? The initrd (from the boot partition) only contains enough of an environment to call the entrypoint for the init system, not contain the entirety of systemd (or the configured services).
Initrd contains the systemd binary and enough libraries, services, and kernel modules to get booted this far. The system failed at switch root which is where the real root disk is mounted. Initrd can contain as much or as little as needed to get a working system which can be a lot of you are using a network filesystem as a root for instance.
Those are all hardware management services (as far as I can tell), and are configured before the root is mounted.
I have hit this exact error before, that is what failing to mount the root disk looks like. A bunch of services will start, and then you get dropped into a shell (with a login).
If you want to see it for yourself, change /etc/fstab such that /root is now pointing to the wrong device, and then rebuild your initrd. When you reboot you'll see exactly that output. To fix it, login to the shell and mount your root on /new_root, and ctrl-d to continue the boot (from memory it has a message telling you to do that anyway). When your system boots you can fix fstab and rebuild initrd. Its reversable, but maybe test on a machine you dont care about to be safe :)
Oh interesting! I suppose I have just been very careful with /etc/fstab and I haven't seen systemd fail this way. TIL! Thanks for letting me know!