Adding Hosts¶

How host auto-discovery works in nix-wire.

Directory layout¶

Hosts live under hosts/ (configurable via the hosts parameter):

hosts/
├── nixos/          # → nixosConfigurations
├── darwin/         # → darwinConfigurations
├── iso/            # → packages.<system>.<name> (ISO images)
└── home/           # → legacyPackages.homeConfigurations (standalone HM)

Two file styles¶

Each host can be defined as either a flat .nix file or a directory with default.nix:

hosts/nixos/
├── laptop.nix              # Flat file → nixosConfigurations.laptop
└── workstation/
    └── default.nix          # Directory → nixosConfigurations.workstation

Precedence

If both foo.nix and foo/default.nix exist, the directory (foo/default.nix) wins. The flat file is silently dropped.

When to use which¶

Flat file - simple configs with no per-user home configs
Directory - when you need a users/ subdirectory for Home Manager

Per-user Home Manager¶

Place user configs in a users/ subdirectory inside any host directory:

hosts/nixos/workstation/
├── default.nix              # System config for "workstation"
└── users/
    ├── alice.nix            # Home config for "alice"
    └── bob/
        └── default.nix      # Home config for "bob" (directory style)

nix-wire automatically:

Creates user entries - users.users.alice and users.users.bob with default home paths (/home/alice, /home/bob)
Wires Home Manager - imports home-manager.nixosModules.home-manager
Sets up per-user configs - home-manager.users.alice imports alice.nix, home-manager.users.bob imports bob/default.nix
Passes special args - inputs and flake available in user configs

User config example¶

# hosts/nixos/workstation/users/alice.nix
{ flake, pkgs, ... }:
{
  home.stateVersion = "25.11";

  imports = [
    flake.homeModules.shell
  ];

  programs.git = {
    enable = true;
    userName = "Alice";
    userEmail = "alice@example.com";
  };

  home.packages = with pkgs; [ ripgrep fd bat ];
}

What every host gets automatically¶

Regardless of the host type (NixOS, Darwin, ISO), every host gets:

Feature	Default	Overridable?
`networking.hostName`	Set to the hostname	Yes (`mkDefault`)
`nixpkgs.config.allowUnfree`	`true`	Yes (`mkDefault`)
`nix.settings.experimental-features`	`["nix-command" "flakes"]`	Yes (`mkDefault`)
`nix.settings.max-jobs`	`"auto"`	Yes (`mkDefault`)
`nixpkgs.overlays`	All overlays from `inputs.self.overlays`	Yes
Home Manager integration	Enabled (if `home = true`)	Via `home` parameter
User discovery	From `users/` subdirectory	Automatic
Special args	`inputs`, `flake`	Automatic

Darwin-specific extras¶

Darwin hosts additionally get sharedModules with session path entries:

home.sessionPath = [
  "/etc/profiles/per-user/$USER/bin"     # home-manager binaries
  "/nix/var/nix/profiles/system/sw/bin"  # nix-darwin binaries
  "/usr/local/bin"                        # macOS GUI programs
];

This ensures home-manager and nix-darwin binaries are on the PATH for zsh/bash sessions on macOS.

Disabling Home Manager¶

If you don't want Home Manager integration for hosts:

outputs = inputs: inputs.nix-wire.mkFlake {
  inherit inputs;
  home = false;
};

This skips importing the home-manager module entirely. The users/ subdirectory is still scanned for user entries, but no Home Manager configs are wired.

Custom host directory name¶

outputs = inputs: inputs.nix-wire.mkFlake {
  inherit inputs;
  hosts = "machines";  # Use machines/ instead of hosts/
};

Now nix-wire looks for machines/nixos/, machines/darwin/, etc.

Building hosts¶

# NixOS
sudo nixos-rebuild switch --flake .#laptop
sudo nixos-rebuild switch --flake .#workstation

# Darwin
darwin-rebuild switch --flake .#macbook
darwin-rebuild switch --flake .#office-mac

# Standalone Home Manager
home-manager switch --flake .#alice