{
  inputs = {
    nixpkgs.url = "github:NixOS/nixpkgs/nixos-unstable";
    nixos-exporter = {
      url = "git+https://git.clerie.de/clerie/nixos-exporter.git";
      inputs.nixpkgs.follows = "nixpkgs";
    };
    solid-xmpp-alarm = {
      url = "git+https://git.clerie.de/clerie/solid-xmpp-alarm.git";
      inputs.nixpkgs.follows = "nixpkgs";
    };
  };
  outputs = { self, nixpkgs, nixos-exporter, solid-xmpp-alarm, ... }: let
    pkgs = import nixpkgs {
      overlays = [
        (import ./pkgs/overlay.nix)
      ];
      system = "x86_64-linux";
    };
    system = "x86_64-linux";
  in {
    nixosConfigurations = let
      generateNixosSystem = name: nixpkgs.lib.nixosSystem {
        system = "x86_64-linux";
        modules = [
          ({ ... }: {
            /*
              Make the contents of the flake availiable to modules.
              Useful for having the monitoring server scraping the
              target config from all other servers automatically.
            */
            _module.args._nixfiles = self;
          })
          ./configuration/common
          ({ ... }: {
            nixpkgs.overlays = [
              (_: _: {
                inherit (nixos-exporter.packages.${system})
                  nixos-exporter;
              })
            ];
          })
          solid-xmpp-alarm.nixosModules.solid-xmpp-alarm
          (./hosts + "/${name}/configuration.nix")
        ];
      };
    in {
      aluminium = generateNixosSystem "aluminium";
      backup-4 = generateNixosSystem "backup-4";
      beryllium = generateNixosSystem "beryllium";
      carbon = generateNixosSystem "carbon";
      clerie-backup = generateNixosSystem "clerie-backup";
      dn42-il-gw1 = generateNixosSystem "dn42-il-gw1";
      dn42-il-gw5 = generateNixosSystem "dn42-il-gw5";
      dn42-il-gw6 = generateNixosSystem "dn42-il-gw6";
      dn42-ildix-clerie = generateNixosSystem "dn42-ildix-clerie";
      gatekeeper = generateNixosSystem "gatekeeper";
      hydra-1 = generateNixosSystem "hydra-1";
      hydra-2 = generateNixosSystem "hydra-2";
      minecraft-2 = generateNixosSystem "minecraft-2";
      monitoring-3 = generateNixosSystem "monitoring-3";
      nonat = generateNixosSystem "nonat";
      osmium = generateNixosSystem "osmium";
      palladium = generateNixosSystem "palladium";
      porter = generateNixosSystem "porter";
      schule = generateNixosSystem "schule";
      storage-2 = generateNixosSystem "storage-2";
      web-2 = generateNixosSystem "web-2";
    };

    colmena = {
      meta = {
        nixpkgs = import nixpkgs {};
      };

      defaults = { name, ... }: {
        deployment = {
          targetHost = "${name}.net.clerie.de";
          targetUser = null;
        };
      };
    } // builtins.mapAttrs (name: host: {
      nixpkgs.system = host.config.nixpkgs.system;
      imports = host._module.args.modules;
      deployment.allowLocalDeployment = builtins.any (n: n == name) [ "schule" "osmium" ];
    }) self.nixosConfigurations;
    packages.x86_64-linux = {
      inherit (pkgs)
        anycast_healthchecker
        flask-excel
        iot-data
        pyexcel-xlsx
        pyexcel-webio
        uptimestatus
        wetter;
    };

    hydraJobs = {
      inherit (self)
        packages;
      nixosConfigurations = builtins.mapAttrs (name: host: host.config.system.build.toplevel) self.nixosConfigurations;
    };
  };
}