NixOS as a daily driver or Zero to Nixty, part 8/? - Modular Config

Published July 20, 2025

4 min read

Check out the whole series here:

Intro

Today is all about configuration and setting up our new encrypted machine. As I stated at the end of the previous post, this didn't go as smoothly as I was hoping.

My plan was to just use labels when setting up the filesystems so my same exact configuration could be copied around. This plan was short-sighted for a number of reasons but it was definitely not going to work after seeing what the basic configuration looked like after installing with encryption enabled. The LUKS device setup is more complex than the normal, unencrypted filesystem config. There may be a way to use labels here but I don't really want to mess with that right now. I have an encrypted machine that boots so I'm going to leave it that way.

Breaking Config Into Modules

After some thinking and research, I decided to refactor the way I store the config. I had been wanting to modularize it a bit anyway, so what better time than now.

First, I broke my config up into some modules in a common directory.

nixos/
├── common
│   ├── base.nix
│   ├── desktop.nix
│   ├── packages.nix
│   ├── services.nix
│   ├── uefi.nix
│   └── users.nix

Then, I created a hosts directory that includes a file for each machine. That file imports these basic modules and adds anything host specific like hostname.

nixos/
├── hosts
│   ├── framework-personal.nix
│   ├── framework-work.nix
│   └── macbook.nix

One of those files looks like this:

{ ... }:

{
  imports = [
    ../common/base.nix
    ../common/users.nix
    ../common/desktop.nix
    ../common/packages.nix
    ../common/services.nix
  ];

  networking.hostName = "macbook";
}

Then I just update the /etc/nixos/configuration.nix that was created for me and import that one module. One of those files looks like this:

{ config, pkgs, ... }:

{
  imports = [
    ./hardware-configuration.nix
    ./hosts/macbook.nix
  ];

  # Replace actual UUID below
  boot.initrd.luks.devices."$UUID".device = "/dev/disk/by-uuid/$UUID";

  # Do not change this value unless you know what you are doing!
  # This value does *not* affect the Nixpkgs version. It is used to determine
  # whether to enable software and configuration options that require backwards
  # compatibility with older NixOS releases. Changing it may result in a system
  # that cannot be upgraded or has other surprising consequences.
  system.stateVersion = "25.05";
}

Complete New Machine Flow

Now, my new machine flow looks something like this:

Install NixOS
Boot up and open a dev shell:

nix-shell -p git rustup neovim

(We use git to check out config, rustup to install rust/dotter, and neovim for easier editing.)
Check out my dotfiles through https for now. This way I don't need to create an SSH key and add it to Github yet:

git clone https://github.com/ducks/dotfiles.git
Install latest Rust then dotter:

rustup install stable; cargo install dotter
Checkout a new branch in my dotfiles dir and add a new host file
Add a new local config for Dotter at

dotfiles/.dotter/local.toml
Use the installed Dotter to deploy my dotfiles:

~/.cargo/bin/dotter deploy
Rebuild NixOS:

sudo nixos-rebuild switch
Start Hypr:

Hyprland
Celebrate! :tada:

If everything went well, I am now sitting behind a duplicate of my other machines. This workflow might seem long but it really only takes 10-30 mins to do all this. It can obviously vary on your machine and build size. It's far easier than any other new machine flow I've tried. I've read about people using ansible to do this kind of thing but this just feels so clean and easy once you get around the rough edges.

I have executed this flow on 3 machines now and it's worked well. I had to make a few small changes like adding a ref to a branch for NixVim, and I'm honestly not sure why that is. I don't think it has anything to do with my config as it was building before.

Summary

In this post, I showed how I broke my NixOS config down into modules so they can be easily imported per host. I think this is a clean and reproducible way to store and share my NixOS config. I have all my base config in easy to use modules, then I can simply add any host specific setup to that single file.

Next Time

At this point, things are feeling pretty good for my setup personally. I keep things pretty minimal so as long as I can navigate around with the correct keybinds and have basic tools like Nix/Neovim and Librewolf installed and setup, I'm mostly good to go. There are definitely some non-NixOS specific things I could pivot to to stick with the "Daily Driver" theme.

If you're reading this and have suggestions or you're curious about something, let me know: nixos@jakegoldsborough.com