nixos/systemd-stage-1: Support resolved

[ElvishJerricco]

Description of changes

This comes with an additional change to put systemd-resolved.service in sysinit.target instead of multi-user.target, given that this is what the upstream unit file indicates in its [Install] section.

Things done

• Built on platform(s)
  • x86_64-linux
  • aarch64-linux
  • x86_64-darwin
  • aarch64-darwin
• For non-Linux: Is sandboxing enabled in nix.conf? (See Nix manual)
  • sandbox = relaxed
  • sandbox = true
• Tested, as applicable:
  • NixOS test(s) (look inside nixos/tests)
  • and/or package tests
  • or, for functions and "core" functionality, tests in lib/tests or pkgs/test
  • made sure NixOS tests are linked to the relevant packages
• Tested compilation of all packages that depend on this change using nix-shell -p nixpkgs-review --run "nixpkgs-review rev HEAD". Note: all changes have to be committed, also see nixpkgs-review usage
• Tested basic functionality of all binary files (usually in ./result/bin/)
• 24.05 Release Notes (or backporting 23.05 and 23.11 Release notes)
  • (Package updates) Added a release notes entry if the change is major or breaking
  • (Module updates) Added a release notes entry if the change is significant
  • (Module addition) Added a release notes entry if adding a new NixOS module
• Fits CONTRIBUTING.md.

---

Add a 👍 reaction to pull requests you find important.

[ElvishJerricco]

This still needs a NixOS test. Help would be greatly appreciated on this, because I'm not actually all that familiar with how to deal with DNS and have already spent hours trying to write a test that I'm pretty sure is nowhere near correct. First, the test should make sure that stage 2 resolved works since AFAICT we don't have a test for that yet, and then we can extend to it to make sure stage 1 works as well.

[ElvishJerricco]

So, I've added a test for systemd-resolved, but I'm not quite satisfied with it in stage 1. I couldn't do the resolvectl query part of the test in stage 1 for some reason. I get this:

example.com: resolve call failed: The name org.freedesktop.resolve1 was not provided by any .service files

And looking back at the logs, I sometimes see something like this,

client # [    1.333575] systemd[1]: systemd-networkd.service: Unexpected error response from GetNameOwner(): Connection terminated
client # [    1.341035] systemd[1]: systemd-resolved.service: Unexpected error response from GetNameOwner(): Connection terminated

Or sometimes something like this,

client # [    1.311828] systemd[1]: Failed to subscribe to NameOwnerChanged signal for 'org.freedesktop.network1': Transport endpoint is not connected
client # [    1.312865] systemd[1]: systemd-networkd.service: Cannot watch bus name org.freedesktop.network1: Transport endpoint is not connected
client # [    1.316867] systemd[1]: Failed to subscribe to NameOwnerChanged signal for 'org.freedesktop.resolve1': Transport endpoint is not connected
client # [    1.317882] systemd[1]: systemd-resolved.service: Cannot watch bus name org.freedesktop.resolve1: Transport endpoint is not connected

Or sometimes nothing indicative of any problems. No matter the logs, I get the resolve call failed error from resolvectl.

[arianvp]

Sounds like dbus is not running

[ElvishJerricco]

@arianvp It is though. If I add print(client.succeed("systemctl status dbus.socket dbus.service")), I get this:

client: must succeed: systemctl status dbus.socket dbus.service
(finished: must succeed: systemctl status dbus.socket dbus.service, in 0.01 seconds)
● dbus.socket - D-Bus System Message Bus Socket
     Loaded: loaded (/etc/systemd/system/dbus.socket; linked; preset: enabled)
     Active: active (running) since Tue 2024-05-21 07:26:24 UTC; 5s ago
   Triggers: ● dbus.service
     Listen: /run/dbus/system_bus_socket (Stream)
     CGroup: /system.slice/dbus.socket

May 21 07:26:24 localhost systemd[1]: Listening on D-Bus System Message Bus Socket.

● dbus.service - D-Bus System Message Bus
     Loaded: loaded (/etc/systemd/system/dbus.service; linked; preset: enabled)
     Active: active (running) since Tue 2024-05-21 07:26:24 UTC; 5s ago
TriggeredBy: ● dbus.socket
       Docs: man:dbus-daemon(1)
   Main PID: 99 (dbus-daemon)
      Tasks: 1 (limit: 1131)
     Memory: 388.0K (peak: 652.0K)
        CPU: 7ms
     CGroup: /system.slice/dbus.service
             └─99 /nix/store/pvyfwb5fyh0max87rkhch4ac4d9b90lq-dbus-1.14.10/bin/dbus-daemon --system --address=systemd: --nofork --nopidfile --systemd-activation --syslog-only

May 21 07:26:24 localhost systemd[1]: Starting D-Bus System Message Bus...
May 21 07:26:24 localhost systemd[1]: Started D-Bus System Message Bus.

And I can see them being started in the log early enough.

[ElvishJerricco]

Ah, we didn't have the necessary dbus files from systemd included. Fixed, and ready for review!

[philiptaron]

This is really sweet! Thank you for your continued grind on making systemd in stage1 work, @ElvishJerricco. Appreciate you.