Declare Hosts & Users

Source

types - schema - examples/microvm

Host Declaration

den.hosts is keyed by <system>.<name>:

{
  den.hosts.x86_64-linux.laptop.users.alice = { };

  den.hosts.aarch64-darwin.mac = {
    users.alice = { };
    brew.apps = [ "iterm2" ];
  };
}

Each host entry produces a configuration in flake.nixosConfigurations or flake.darwinConfigurations depending on its class (auto-detected from the host platform).

Host Schema

Important

Be sure to read about the entity Schemas, each of host/user/home has a corresponding den.schema.* module for meta-configuration of entity features. Which can later be used in aspects that read from host. These schemas are the meta-data equivalent of what Dendritic flake-parts users do with flake-level options.

Hosts have these options (all with sensible defaults):

Option	Default	Description
name	attrset key	Configuration name
hostName	name	Network hostname
system	parent key	x86_64-linux, aarch64-darwin, etc.
class	"nixos" or "darwin"	OS class, auto-detected from system
aspect	name	Primary aspect name
instantiate	class-dependent	lib.nixosSystem, darwinSystem, etc.
intoAttr	class-dependent	Flake output path
users	{}	User account definitions
*	from den.schema.host	Any option defined by base module
*		Any other free-form attribute

User Declaration

Users are declared as part of a host:

den.hosts.x86_64-linux.laptop = {
  users.alice = { };
  users.bob.classes = [ "homeManager" "hjem" ];
};

Each user has:

Option	Default	Description
name	attrset key	User configuration name
userName	name	System account name
aspect	name	Primary aspect name
classes	[ "homeManager" ]	Nix classes this user participates in
*	from den.schema.user	Any option defined by base module
*		Any other free-form attribute

Standalone Homes

For systems without root access or for home-manager-only setups:

{
  den.homes.x86_64-linux.alice = { };
  den.homes.aarch64-darwin.alice = { };
}

Standalone homes produce flake.homeConfigurations.<name>.

Home schema:

Option	Default	Description
name	attrset key	Home configuration name
userName	name	User account name
system	parent key	Platform system
class	"homeManager"	Home class
aspect	name	Primary aspect name
pkgs	inputs.nixpkgs.legacyPackages.${system}	nixpkgs instance
instantiate	inputs.home-manager.lib.homeManagerConfiguration	Builder function
*	from den.schema.host	Any option defined by base module
*		Any other free-form attribute

Base Modules

den.schema.{host,user,home} provides shared configuration applied to all entities of each kind.

Some batteries also extend base modules see home-env.nix that is used by home-manager/hjem/maid to extend the Host schema with options like hjem.module/home-manager.module.

Another more advanced examples is our templates/microvm that adds options related to running virtualized OS.

{
  # Can be used to specify features of all host
  den.schema.host.home-manager.enable = true;

  # Can be used to add schema options with defaults
  den.schema.user = { user, lib, ... }: {
    options.groupName = lib.mkOption { default = user.userName; };
  };

  # Applied to every host and user and home.
  den.schema.conf = {
    options.copyright = lib.mkOption { default = "Copy-Left"; };
  };
}

Freeform Schema

Host and user types use freeformType, so you can add arbitrary attributes:

den.hosts.x86_64-linux.laptop = {
  users.alice = { };
  gpu = "nvidia";  # custom attribute, accessible in aspects via host.gpu
};

Access custom attributes in aspects:

den.aspects.laptop.includes = [
  ({ host, ... }: lib.optionalAttrs (host ? gpu) {
    nixos.hardware.nvidia.enable = true;
  })
];