Re: Getting boottime early in booting

On Fri, Apr 3, 2026 at 6:05 PM Rick Macklem <[email protected]> wrote:
>
> Hi,
>
> I'm fiddling with a NFSv4 diskless root fs setup and I've run
> into a couple of challenges.
>
> 1 - I need a value that will be different each time the machine boots.
>      I would normally use getboottime(), but for the NFS root fs mount,
>      it just returns 0.
>      Any ideas w.r.t. something I can acquire early in booting that will
>      change each time the system is booted?
>
> 2 - Does anyone know how to fix "could not determine audit condition"
>      which I get whenever I try and login when it is multiuser?
>      (I can run single user, but since I can't login once it's multiuser??)
Btw, in case anyone is interested, #2 was caused by the conf/base/var.cpio.gz
file (used to create the md fs for /var) was too big for a 5Mbyte md.
(Getting rid of some stuff in it fixed the problem.)

I now have a NFSv4.2 root fs working ok, thanks to some help here
w.r.t. getting a new value upon each boot.

https://docs-archive.freebsd.org/doc/8.4-RELEASE/usr/share/doc/freebsd/handbook/network-pxe-nfs.html
is pretty good, but does miss a couple of things. There's making sure the
files for the md file systems aren't too big (or configuring the md's
to be larger)
and there's /tmp, which isn't mentioned.
--> There is also dealing with setting up hostuuid when there are multiple
     clients using the read-only root fs.
      I'm not quite sure what is appropriate here?
      - Maybe making /etc/hostid a symlink to a file in /var and then
        having /etc/rc.d/hostid create the file when it doesn't exist, or
        something like that. (For systems that don't have smbios.system.uuid
        this would result in a different setting each boot, but the
only alternative
        I can think of would be a site local DHCPD option to specify it.
        (This isn't a NFSv4 problem, but a shared read-only root fs problem.)

Anyhow, if someone on the doc side feels like improving the above a little,
that would be nice, rick

>
> Thanks for any help with these, rick