[systemd-devel] what dependencies does systemd itself have on underlying system?

Lennart Poettering lennart at poettering.net
Tue Aug 23 08:48:49 PDT 2011

On Mon, 22.08.11 17:29, John Lumby (johnlumby at hotmail.com) wrote:

> Mike Kazantsev wrote:
> >
> > Some stuff is listed in the README file (REQUIREMENTS and WARNINGS
> > sections), but it doesn't really covers all possible misconfigurations,
> > of course.
> >
> > To figure out what exactly goes wrong, I think it might help to disable
> > pymouth, remove "quiet" from kernel cmdline and add somehing like
> > "systemd.log_level=debug systemd.log_target=kmsg" there (see systemd(1)
> > and kernel Documentation on cmdline parameters).
> >
> Thanks Mike.    I tried that but there were no log messages.    But
> then it dawned on me what the cause of the problem (with custom
> kernel) was :
> systemd was reporting this on the console:
>         Failed to mount /dev: No such device
> This made no sense to me until I checked what the errno
> corresponding to this  and what causes that errno from a mount() :
>      ENODEV filesystemtype not configured in the kernel.
> So that was my "misconfiguration".       Mentioning it in case
> anyone else hits this and is baffled.

You need devtmpfs enabled in the kernel, as documented in the README.

> Also  -  just a thought  -  maybe systemd should treat this as a
> warning rather than a showstopper and try to carry on  (i.e. use the
> existing /dev structure);    in my case it would (I believe) have
> come up ok plus or minus a few trivial parts.     And,  yes  -  now
> I see devtmpfs is stated in the README REQUIREMENTS    :-X

We do not support non-devtmpfs /dev really. The device nodes from a
previous boot would not have the right major/minor/attrs for the current
boot. You really do need devtmpfs.


Lennart Poettering - Red Hat, Inc.

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