`systemd-networkd-wait-online` with `networking.useNetworkd` broken as of systemd 253.6

[winterqt]

https://github.com/NixOS/nixpkgs/blob/48fecd04896121f8af12ff33754ef251d4ae6318/nixos/modules/tasks/network-interfaces-systemd.nix#L62-L70

This configuration has worked fine until https://github.com/systemd/systemd/commit/2f96a29c2c55bdd67cdd8e0b0cfd6971968e4bca, which now makes it so wait-online will indefinitely hang if no managed interfaces are configured that have RequiredForOnline set, which our default configuration for networking.useNetworkd does not.

@NixOS/systemd (specifically @ElvishJerricco, as the original author of the above configuration), how do we want to handle this?

[arianvp]

I can reproduce

[Mic92]

Yes. It's broken and we also disables this in srvos everywhere: https://github.com/numtide/srvos/blob/85fed23fce8ada8017486090569c0a9054875d5c/nixos/common/networking.nix#L17

[ElvishJerricco]

specifically @ElvishJerricco, as the original author of the above configuration

(FWIW I am not the original author of that code; git blames me because I re-indented it and added a little bit of systemd-initrd logic)

[Majiir]

I ran into this with systemd.network.enable without networking.useNetworkd. I had no interfaces configured with networkd. While this isn't a particularly useful configuration, :slightly_smiling_face: it shouldn't cause system activation to hang.

[ElvishJerricco]

This will be fixed by #258680, no?

[misuzu]

I've just run into this on the latest nixos-unstable, this combination triggers the issue:

networking.useNetworkd = true;
networking.networkmanager.enable = true;

systemd.network.wait-online.anyInterface = true; doesn't help

https://github.com/NixOS/nixpkgs/pull/258680 was reverted in https://github.com/NixOS/nixpkgs/pull/283818

[akvadrako]

Related issue: https://github.com/systemd/systemd/issues/25813