Issue with dracut 048 and Ubuntu

[Andrew Ruthven]

[Time to rewrite this a third time as I've learnt more! But I'll
include some of my learning steps in the hope that if people find this
via web searches it might resolve their issues.]

Hey,

I've just spent the past few hours tearing my hair out trying to get a
build to work. Finally got there! 

The nfsroot: Stretch, FAI 5.7.2 and initially dracut 048.
The server: Ubuntu Trusty (I know), with FAI 5.3.2 from the FAI PPA.

The root cause of my issue was that fai-make-nfsroot bailed out of
building my nfsroot because of this error:

mount: mount point /srv/fai/nfsroot.stretch/dev/pts does not exist

I didn't think too much about that, but noticed no kernel was installed
so then ran:

fai-make-nfsroot -k

But, I found that dracut 048 (from fai-project repo) wouldn't mount my
nfsroot, with the dreaded "nfs: Protocol not supported" error. I
started out with a 4.18 backports kernel (to try and support a new
network card), then 4.17, then finally the Stretch 4.9 kernel. Still
busted.

I checked my other nfsroots, and they're all using dracut 044, so I
downgraded. Bingo, working.

Next issue was that I didn't get a /etc/init.d/rcS symlink pointing to
/usr/sbin/fai. I've never had that issue before! I manually created the
symlink and managed to get a server build to work.

But this didn't feel right, so I dug a bit more. Turns out that mount
up above failed because for whatever reason, $NFSROOT/dev/pts didn't
exist so the mount call in upgrade_nfsroot() failed.

Adding a mkdir -p $NFSROOT/dev/pts before the mount resolved the issue.
And now I have a working nfsroot, with dracut 048 in it. I haven't
tried the 4.18 kernel as it turns out the 4.9 kernel supports these
network cards.

This might just be an issue on Trusty, not sure, but Thomas, what do
you think about adding that mkdir -p?

Cheers,
Andrew
-- 
Andrew Ruthven, Wellington, New Zealand
andrew at etc.gen.nz        | linux.conf.au 2019, Christchurch, NZ
https://catalystcloud.nz |     https://lca2019.linux.org.au