/etc/resolv.conf contents reversed after rebuilding nfsroot

Thomas Lange lange at informatik.uni-koeln.de
Wed Oct 9 21:57:22 CEST 2019

Hi Merlin,

if I understand your correct, the resolv.conf inside the nfsroot is
always correct.

Upgrading the nfsroot using -kvp did not rebuild the whole nfsroot, it
just upgraded it without changing resolv.conf

Using fai-make-nfsroot -fvp rebuilds the whole nfsroot.
But building the nfsroot just copies the /etc/resolv.conf from the FAI
install server into the nfsroot. This should/can not reverse the
order of the entries in resolv.conf.

When the client does a network installation using PXE it uses the
resolv.conf from the config space or from inside the nfsroot.
See lib/subroutines line 1066ff
We also use lib/create_resolv_conf which copies the resolv.conf from
the initrd (created by dracut) or loops through the list defined by
$DNSSRVS (which comes from the DHCP server and is created by ./lib/dhclient-perl).

The difference between 5.3.6 and 5.8.x may be that we copy the
resolv.conf from the config space nowadays. IIRC we did not that
before. But I'm not sure. Maybe the order of the nameserver in
$DNSSRVS was always reversed but noone had problems with it.

So, please check all resolv.conf versions (on the FAI server itself, in the
nfsroot, inside the initrd, on the client) and tell which are the
wrong version. Maybe change all cp commands of a resolv.conf to cp -v.
Also check the order of DNS servers in dhcpd.conf on your dhcp server.

regards Thomas

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