Comment 11 for bug 1981103

*This* bug has the full information in the first post including all needed to fix the problem. Actually there are more problems in the script regarding syntax, so more issues exist, leading to unwanted behavior.

Uwe

Am 22. Oktober 2022 22:05:59 MESZ schrieb David Kowis <email address hidden>:
>https://bugs.launchpad.net/ubuntu/+source/ifupdown/+bug/1910273
>
>This one seems to have the full patch repair in the bug description.
>None of the other bugs I've found relating to this have the full
>solution.
>
>--
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>report.
>https://bugs.launchpad.net/bugs/1981103
>
>Title:
> System with DNS server in /etc/network/interfaces has bogus systemd-
> resolved config after upgrade to 22.04
>
>Status in ifupdown package in Ubuntu:
> Triaged
>
>Bug description:
> Description: Ubuntu 22.04 LTS
> Release: 22.04
>
> ifupdown:
> Installed: 0.8.36+nmu1ubuntu3
> Candidate: 0.8.36+nmu1ubuntu3
> Version table:
> *** 0.8.36+nmu1ubuntu3 500
> 500 http://de.archive.ubuntu.com/ubuntu jammy/universe amd64 Packages
> 100 /var/lib/dpkg/status
>
> After upgrading a server with classic ifupdown configuration after
> reboot the machine had no valid dns servers anymore.
>
> The problem is that the state file created by ifupdown using
> /etc/network/if-up.d/resolved looks like this:
>
> root@pangaea-pm:~# cat /run/network/ifupdown-inet-ens13
> "DNS"="134.102.20.20 134.102.200.14"
> "DOMAINS"="marum.de"
>
> The script later sources this file and causes the following errors,
> easy to see when you execute this:
>
> root@pangaea-pm:~# ifdown ens13; ifup ens13
> /etc/network/if-down.d/resolved: 12: mystatedir: not found
> /etc/network/if-up.d/resolved: 12: mystatedir: not found
> /etc/network/if-up.d/resolved: 71: DNS: not found
> /etc/network/if-up.d/resolved: 1: /run/network/ifupdown-inet-ens13: DNS=134.102.20.20 134.102.200.14: not found
> /etc/network/if-up.d/resolved: 2: /run/network/ifupdown-inet-ens13: DOMAINS=marum.de: not found
> Failed to parse DNS server address: DNS
> Failed to set DNS configuration: Invalid argument
>
> This happened to me on three different servers, so this is a serious
> bug and should be fixed before 22.04 upgrades are allowed for
> everybody. Most servers provided by data centers like Hetzner
> (Germany) are configure like that. After a do-release-upgrade you have
> no working DNS anymore, unless you disable systemd-resolved. I don't
> want to use netplan, so changing to this is no option.
>
> The fix is easy - remove the quotes in the script on the left side
> "$DNS" => $DNS; same for DOMAINS:
>
> if [ -n "$NEW_DNS" ]; then
> cat <<EOF >"$mystatedir/ifupdown-${ADDRFAM}-$interface"
> $DNS="$NEW_DNS"
> EOF
> if [ -n "$NEW_DOMAINS" ]; then
> cat <<EOF >>"$mystatedir/ifupdown-${ADDRFAM}-$interface"
> $DOMAINS="$NEW_DOMAINS"
> EOF
> fi
> fi
>
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>

--
Uwe Schindler
Achterdiek 19, 28357 Bremen
https://www.thetaphi.de