On 11/21/2016 10:17 PM, Bruce Dubbs wrote:
Douglas R. Reno wrote:
On Mon, Nov 21, 2016 at 8:18 PM, Bruce Dubbs <[email protected]>
wrote:
Eric Stone wrote:
Unless I made a mistake following the book, it seems 7.10-systemd
installations are unable to boot into linux single-user mode without
modification. When “single” is added to the kernel boot parameters,
Systemd’s rescue.target (aka runlevel 1) looks for “sulogin” in a
different
location than where it’s installed by following the LFS book.
Because of
this, systemd just transitions on to the usual graphical.target mode
(aka
runlevel 5). I fixed this on my system by issuing:
sudo ln -s /sbin/sulogin /usr/sbin/sulogin
I’m not certain what a better long-term fix for LFS is; move the
sulogin
executable (like “passwd” gets moved per LFS instructions after
installing
“shadow”), patch systemd to use the current location, or add a symlink
like
I did. Regardless it would be helpful to add this note to 7.10-systemd
errata, and improve the next LFS-systemd release.
We still support the possibility of a separate /usr partition, so it
would
appear that the best solution is to fix systemd.
I don't do systemd very often, so I could be mistaken, but it appears
that
ac_cv_path_SULOGIN="/sbin/sulogin"
in config.cache would do what is needed.
Actually SULOGIN="/sbin/sulogin" was sufficient.
systemd itself explicitly does not support a split /usr.
https://freedesktop.org/wiki/Software/systemd/separate-usr-is-broken/
Just because systemd doesn't does not mean that we shouldn't try. From
the above link:
"One thing in advance: systemd itself is actually completely fine with
/usr on a separate file system that is not pre-mounted at boot time.
However, the common basic set of OS components of modern Linux machines
is not, and has not been in quite some time. And it is unlikely that
this is going to be fixed any time soon, or even ever."
There really a lot of need to do much to mount /usr after the initial
boot. In some cases networking may be needed for a nfs or smb mount.
We do put the files needed in /bin and /lib so the reference about
"common basic set of OS components" not being available is not accurate
for LFS.
-- Bruce
Yes, we covered this fairly well when udev was merged with systemd. I
think there are a couple of corner cases, but nothing critical. AFAICT,
not much has changed. See the follow-up article linked from that document:
https://www.freedesktop.org/wiki/Software/systemd/TheCaseForTheUsrMerge/
Specifically: "systemd supports both systems with split and with merged
/usr..." I'd say at best, it's a bit fuzzy. I don't have a link right
now, but I know that the split-usr switch was said not to be going away
anytime soon when these articles were new. That may have changed, but it
still exists, and we still have it in the book.
All of that said, I agree with the merged /usr direction, but I'm not
ready to propose that for LFS. I think too much info would be lost while
it still works well. I imagine we'll be forced to do it with systemd at
some point in the future, but for now, we are OK, AFAIK.
--DJ
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