dhcpcd-discuss

On 10/11/2020 09:20, Jan Pohanka wrote:
> > Do you have any other application competeing to write to resolv.conf?
> > Do you have resolvconf(8) installed to manage this? I also maintain openresolv,
> > which is a good resolvconf implementation.
>
> As far as I know there is nothing that could write to resolv.conf
> file. I also do not have resolvconf(8), I'm trying to keep my embedded
> system as lightweight as possible.
>
> > The hook script to manage resolv.conf has hardly changed from 8.0.3 and there is
> > nothing that stands out to say "this is the issue".
>
> Would you advise to upgrade?  Probably yes, I understand :)

Well, let's try and fine the issue first.
I understand you want to keep the system light and dhcpcd's "poor man 
resolvconf" should still work fine *if* only dhcpcd is touching resolv.conf

Let's try and add some extreme debugging!

Try adding this to /etc/dhcpcd.enter-hook

# Redirect stdout to /var/log/dhcpcd-hooks.log and stderr to stdout
exec 1<&-
exec 2<&-
exec 1>/var/log/dhcpcd-hooks.log
exec 2>&1

echo "Starting dhcpcd hook debug"
# Enable shell debugging
set -x

And this in /etc/dhcpcd.exit-hook
set +x
echo "Ending dhcpcd hook debug"

Do your test a few times and when /etc/resolv.conf is blank hopefully the above 
mentioned log file will have loads of data we can look at.

Roy