Matthew Sanabria’s Nix Configuration

Nix configuration to manage multiple machines declaratively.

Requirements

• Determinate Nix

Machines

Name	System	Type
ms-macbook-air	aarch64-darwin	nix-darwin
ms-fw-desktop	x86_64-linux	NixOS

Layout

• flake.nix — entry point, inputs, and the apply dev shell

• lib/ — mksystem.nix (system builder) and identity.nix (personal data)

• modules/ — common.nix, darwin.nix, nixos.nix

• home/ — home-manager modules (one file per program)

• machines/<host>/ — per-machine overrides and hardware config

Usage

Enter the development shell.

nix develop

Apply the configuration for the current machine. The apply script only rebuilds the local machine; it does not deploy to remote hosts.

apply

Apply a different host’s configuration explicitly (useful for testing a config locally before deploying it). Extra arguments are forwarded to the underlying darwin-rebuild / nixos-rebuild.

apply ms-fw-desktop
apply ms-fw-desktop --show-trace

Or, without entering the shell first.

nix develop --command apply

Format all Nix files.

nix fmt .

State Versions

system.stateVersion (NixOS / nix-darwin) and home.stateVersion (home-manager) are recorded once when a host is first installed and should not be bumped without first reading the corresponding release notes. They exist so option defaults remain stable across upgrades; changing them can silently alter system behavior.

Bootstrap

For a new macOS machine, run the following to bootstrap. The URL pins nix-darwin to the same 0.1 series used by flake.nix for reproducibility.

nix run https://flakehub.com/f/nix-darwin/nix-darwin/0.1 -- \
  switch --flake .#ms-macbook-air

For a new NixOS machine, first boot the official NixOS installer, then clone this repository onto the target machine and generate a hardware config for the host (see machines/ms-fw-desktop/hardware.nix for an example — that file was produced by nixos-generate-config and is host-specific). Once a machine module exists, run:

sudo nixos-rebuild switch --flake .#ms-fw-desktop