Write a Hive

Anatomy of a Hive

A "Hive" is the attribute set that you pass to wire.makeHive. It has the following layout:

# `meta`
# type: attrset
meta = {
    # `meta.nixpkgs` tells wire how to get nixpkgs.
    # type: "A path or an instance of nixpkgs."
    nixpkgs = <nixpkgs>;

    # `meta.specialArgs` are specialArgs to pass to each node & default
    # type: attrset
    specialArgs = { };

    # `meta.nodeNixpkgs` lets you override nixpkgs per-node.
    # type: attrset of "A path or an instance of nixpkgs."
    nodeNixpkgs: = { };
};

# `defaults` is a module applied to every node
# type: NixOS Module
defaults = { ... }: { };

# Any other attributes are nodes.

<node-name>

Other attributes are NixOs modules that describe a system. They automatically have defaults and the wire NixOS module imported.

They also have the name and nodes attributes passed to them, name being a string of the nodes name, and nodes being an attribute set of every node in the hive.

meta

There is more detailed information about meta in the reference.

defaults

De-duplicate options with default node configuration.

At the top level of a hive wire reserves the defaults attribute. It's applied to every node.

WARNING

defaults must not rely on modules that a node imports, but a node may rely on modules that default imports.

Example

There is more detailed information the special options for nodes the reference.

hive.nix

{
  meta.nixpkgs = import some-sources-or-inputs.nixpkgs { };

  defaults = {
    # name of the node that defaults is being applied to
    name,
    # attribute set of all nodes
    nodes,
    pkgs,
    ...
  }: {
    import = [
      ./default-module.nix

      # module that is imported for all nodes
      some-flake.nixosModules.default
    ];

    # all nodes should include vim!
    environment.systemPackages [ pkgs.vim ];
  };

  node-a = {
    # name of the node that defaults is being applied to
    name,
    # attribute set of all nodes
    nodes,
    pkgs,
    ...
  }: {
    imports = [
      # import the hardware-config and all your extra stuff
      ./node-a
    ];

    deployment = {
      target.host = "192.0.2.1";
      tags = [ "x86" ];
    };
  };

  # as many nodes as you'd like...

  node-g = {
    # some more config
  };
}