Why is `systemd-networkd-wait-online.service` masked

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1

Why is systemd-networkd-wait-online.service masked on Nixos? I have created a service that should wait for the network to be available. I noticed that after reboot, this service start before the network is completely online. What is the correct way in Nix to force a service to wait until the network (maybe even specific interfaces) to be online?

    systemd.services."ampero-config" = rec {
      serviceConfig = {
        Type = "oneshot";
        DynamicUser = "yes";
      };
      after = [ "network-online.target" ];
      wants = [ "network-online.target" ];
      ...

$ systemctl status systemd-networkd-wait-online.service
○ systemd-networkd-wait-online.service
     Loaded: masked (Reason: Unit systemd-networkd-wait-online.service is masked.)
     Active: inactive (dead)
2

Are you using networkd?

3

If yes, do you also have systemd.network.wait-online.enable set in your config (the default is true)?

4

yes

systemd.network.enable = true;
5

There are no settings in my config for systemd.network.wait-online.enable so it should default to true. But I found out that when I set it to true in my config I get this error:

       error: The option `systemd.network.wait-online.enable' has conflicting definition values:
       - In `/nix/store/rjsk8c698ar6acycydk6vbanangpd87k-source/nixos/common/networking.nix': false
       - In `/nix/store/q4j2qpm4zl7ifp93ihfd6qs6zd40i6xb-source/hosts/common/global/network.nix': true

The contents of /nix/store/rjsk8c698ar6acycydk6vbanangpd87k-source/nixos/common/networking.nix is:

{ lib, ... }:
{
  # Allow PMTU / DHCP
  networking.firewall.allowPing = true;

  # Keep dmesg/journalctl -k output readable by NOT logging
  # each refused connection on the open internet.
  networking.firewall.logRefusedConnections = lib.mkDefault false;

  # Use networkd instead of the pile of shell scripts
  networking.useNetworkd = lib.mkDefault true;

  # The notion of "online" is a broken concept
  # https://github.com/systemd/systemd/blob/e1b45a756f71deac8c1aa9a008bd0dab47f64777/NEWS#L13
  systemd.services.NetworkManager-wait-online.enable = false;
  systemd.network.wait-online.enable = false;

  # FIXME: Maybe upstream?
  # Do not take down the network for too long when upgrading,
  # This also prevents failures of services that are restarted instead of stopped.
  # It will use `systemctl restart` rather than stopping it with `systemctl stop`
  # followed by a delayed `systemctl start`.
  systemd.services.systemd-networkd.stopIfChanged = false;
  # Services that are only restarted might be not able to resolve when resolved is stopped before
  systemd.services.systemd-resolved.stopIfChanged = false;
}

Looks like srvos/nixos/common/networking.nix at c877dc6f7920b373e5943f77377e6ef816f4dc30 · nix-community/srvos · GitHub is causing this behaviour.