Comment 15 for bug 1891215

Verification for Focal (245.4-4ubuntu3.8)

# Initial repro on focal:

root@focal:~# md5sum /etc/resolv.conf; stat -t -L /etc/resolv.conf
fbfde622ae28a4dcfbf73a397a10c6ae /etc/resolv.conf
/etc/resolv.conf 717 8 81a4 101 103 76 123 1 0 0 1625844292 1625844273 1625844273 0 4096
root@focal:~# ip link set eth0 down; sleep 1; ip link set eth0 up
root@focal:~# md5sum /etc/resolv.conf; stat -t -L /etc/resolv.conf
fbfde622ae28a4dcfbf73a397a10c6ae /etc/resolv.conf
/etc/resolv.conf 717 8 81a4 101 103 76 123 1 0 0 1625844310 1625844308 1625844308 0 4096

# Upgrading to -proposed

root@focal:~# apt update && apt-get dist-upgrade -V
Get:1 http://security.ubuntu.com/ubuntu focal-security InRelease [114 kB]
Hit:2 http://archive.ubuntu.com/ubuntu focal InRelease
Get:3 http://archive.ubuntu.com/ubuntu focal-updates InRelease [114 kB]
Get:4 http://archive.ubuntu.com/ubuntu focal-proposed InRelease [267 kB]
Get:5 http://archive.ubuntu.com/ubuntu focal-updates/main amd64 Packages [1,086 kB]
Get:6 http://archive.ubuntu.com/ubuntu focal-updates/main Translation-en [239 kB]
Get:7 http://archive.ubuntu.com/ubuntu focal-updates/universe amd64 Packages [840 kB]
Get:8 http://archive.ubuntu.com/ubuntu focal-proposed/restricted amd64 Packages [191 kB]
Get:9 http://archive.ubuntu.com/ubuntu focal-proposed/restricted Translation-en [27.2 kB]
Get:10 http://archive.ubuntu.com/ubuntu focal-proposed/main amd64 Packages [203 kB]
Get:11 http://archive.ubuntu.com/ubuntu focal-proposed/main Translation-en [42.2 kB]
Get:12 http://archive.ubuntu.com/ubuntu focal-proposed/multiverse amd64 Packages [18.2 kB]
Get:13 http://archive.ubuntu.com/ubuntu focal-proposed/multiverse Translation-en [6,732 B]
Get:14 http://archive.ubuntu.com/ubuntu focal-proposed/universe amd64 Packages [56.2 kB]
Get:15 http://archive.ubuntu.com/ubuntu focal-proposed/universe Translation-en [24.5 kB]
Fetched 3,229 kB in 2s (1,428 kB/s)
Reading package lists... Done
Building dependency tree
Reading state information... Done
9 packages can be upgraded. Run 'apt list --upgradable' to see them.
Reading package lists... Done
Building dependency tree
Reading state information... Done
Calculating upgrade... Done
The following packages will be upgraded:
   libgnutls30 (3.6.13-2ubuntu1.3 => 3.6.13-2ubuntu1.5)
   libnss-systemd (245.4-4ubuntu3.7 => 245.4-4ubuntu3.8)
   libpam-systemd (245.4-4ubuntu3.7 => 245.4-4ubuntu3.8)
   libsystemd0 (245.4-4ubuntu3.7 => 245.4-4ubuntu3.8)
   libudev1 (245.4-4ubuntu3.7 => 245.4-4ubuntu3.8)
   systemd (245.4-4ubuntu3.7 => 245.4-4ubuntu3.8)
   systemd-sysv (245.4-4ubuntu3.7 => 245.4-4ubuntu3.8)
   systemd-timesyncd (245.4-4ubuntu3.7 => 245.4-4ubuntu3.8)
   udev (245.4-4ubuntu3.7 => 245.4-4ubuntu3.8)
9 upgraded, 0 newly installed, 0 to remove and 0 not upgraded.
Need to get 6,672 kB of archives.
After this operation, 15.4 kB of additional disk space will be used.
Do you want to continue? [Y/n]
Get:1 http://archive.ubuntu.com/ubuntu focal-proposed/main amd64 libnss-systemd amd64 245.4-4ubuntu3.8 [96.1 kB]
Get:2 http://archive.ubuntu.com/ubuntu focal-proposed/main amd64 udev amd64 245.4-4ubuntu3.8 [1,365 kB]
Get:3 http://archive.ubuntu.com/ubuntu focal-proposed/main amd64 libudev1 amd64 245.4-4ubuntu3.8 [78.4 kB]
Get:4 http://archive.ubuntu.com/ubuntu focal-proposed/main amd64 systemd-sysv amd64 245.4-4ubuntu3.8 [10.3 kB]
Get:5 http://archive.ubuntu.com/ubuntu focal-proposed/main amd64 systemd-timesyncd amd64 245.4-4ubuntu3.8 [28.1 kB]
Get:6 http://archive.ubuntu.com/ubuntu focal-proposed/main amd64 libpam-systemd amd64 245.4-4ubuntu3.8 [186 kB]
Get:7 http://archive.ubuntu.com/ubuntu focal-proposed/main amd64 libgnutls30 amd64 3.6.13-2ubuntu1.5 [828 kB]
Get:8 http://archive.ubuntu.com/ubuntu focal-proposed/main amd64 systemd amd64 245.4-4ubuntu3.8 [3,810 kB]
Get:9 http://archive.ubuntu.com/ubuntu focal-proposed/main amd64 libsystemd0 amd64 245.4-4ubuntu3.8 [271 kB]
Fetched 6,672 kB in 3s (2,541 kB/s)
(Reading database ... 14718 files and directories currently installed.)
Preparing to unpack .../libnss-systemd_245.4-4ubuntu3.8_amd64.deb ...
Unpacking libnss-systemd:amd64 (245.4-4ubuntu3.8) over (245.4-4ubuntu3.7) ...
Preparing to unpack .../udev_245.4-4ubuntu3.8_amd64.deb ...
Unpacking udev (245.4-4ubuntu3.8) over (245.4-4ubuntu3.7) ...
Preparing to unpack .../libudev1_245.4-4ubuntu3.8_amd64.deb ...
Unpacking libudev1:amd64 (245.4-4ubuntu3.8) over (245.4-4ubuntu3.7) ...
Setting up libudev1:amd64 (245.4-4ubuntu3.8) ...
(Reading database ... 14718 files and directories currently installed.)
Preparing to unpack .../systemd-sysv_245.4-4ubuntu3.8_amd64.deb ...
Unpacking systemd-sysv (245.4-4ubuntu3.8) over (245.4-4ubuntu3.7) ...
Preparing to unpack .../systemd-timesyncd_245.4-4ubuntu3.8_amd64.deb ...
Unpacking systemd-timesyncd (245.4-4ubuntu3.8) over (245.4-4ubuntu3.7) ...
Preparing to unpack .../libpam-systemd_245.4-4ubuntu3.8_amd64.deb ...
Unpacking libpam-systemd:amd64 (245.4-4ubuntu3.8) over (245.4-4ubuntu3.7) ...
Preparing to unpack .../libgnutls30_3.6.13-2ubuntu1.5_amd64.deb ...
Unpacking libgnutls30:amd64 (3.6.13-2ubuntu1.5) over (3.6.13-2ubuntu1.3) ...
Setting up libgnutls30:amd64 (3.6.13-2ubuntu1.5) ...
(Reading database ... 14718 files and directories currently installed.)
Preparing to unpack .../systemd_245.4-4ubuntu3.8_amd64.deb ...
Unpacking systemd (245.4-4ubuntu3.8) over (245.4-4ubuntu3.7) ...
Preparing to unpack .../libsystemd0_245.4-4ubuntu3.8_amd64.deb ...
Unpacking libsystemd0:amd64 (245.4-4ubuntu3.8) over (245.4-4ubuntu3.7) ...
Setting up libsystemd0:amd64 (245.4-4ubuntu3.8) ...
Setting up udev (245.4-4ubuntu3.8) ...
Setting up systemd (245.4-4ubuntu3.8) ...
Installing new version of config file /etc/dhcp/dhclient-enter-hooks.d/resolved ...
Setting up systemd-timesyncd (245.4-4ubuntu3.8) ...
Setting up systemd-sysv (245.4-4ubuntu3.8) ...
Setting up libnss-systemd:amd64 (245.4-4ubuntu3.8) ...
Setting up libpam-systemd:amd64 (245.4-4ubuntu3.8) ...
Processing triggers for libc-bin (2.31-0ubuntu9.2) ...
Processing triggers for dbus (1.12.16-2ubuntu2.1) ...

# Config the fix worked:

root@focal:~# md5sum /etc/resolv.conf; stat -t -L /etc/resolv.conf
fbfde622ae28a4dcfbf73a397a10c6ae /etc/resolv.conf
/etc/resolv.conf 717 8 81a4 101 103 76 50 1 0 0 1625844400 1625844368 1625844368 0 4096
root@focal:~# ip link set eth0 down; sleep 1; ip link set eth0 up
root@focal:~# md5sum /etc/resolv.conf; stat -t -L /etc/resolv.conf
fbfde622ae28a4dcfbf73a397a10c6ae /etc/resolv.conf
/etc/resolv.conf 717 8 81a4 101 103 76 50 1 0 0 1625844407 1625844368 1625844368 0 4096