nix-starter-configs/README.md

Nix Starter Config

This is a simple nix flake for getting started with NixOS + home-manager.

What this provides

• NixOS configuration on nixos/configuration.nix, accessible via nixos-rebuild --flake .
• Home-manager configuration on home-manager/home.nix, accessible via home-manager --flake .
• Basic boilerplate for adding custom packages (under pkgs) and overlays (under overlays). Accessible on your system, home config, as well as nix build .#package-name
• Boilerplate for custom NixOS (modules/nixos) and home-manager (modules/home-manager) modules

Getting started

Assuming you have a basic NixOS booted up (either live or installed, anything works). Here's a link to the latest NixOS downloads, just for you.

The repo

• Install git

• Hit "Use this template" on this repo (or clone this down and push to any another git remote)

• Add stuff you currently have on /etc/nixos/ to nixos (usually configuration.nix and hardware-configuration.nix, when you're starting out).

  • The included file has some options you might want, specially if you don't have a configuration ready. Make sure you have generated your own hardware-configuration.nix; if not, just mount your partitions to /mnt and run: nixos-generate-config --root /mnt.

• If you're already using home-manager, add your stuff from ~/.config/nixpkgs to home-manager (probably home.nix).

  • I also include one with some simple options if you need. Feel free to ignore this step if you don't want to use home-manager just yet.

• Take a look at flake.nix, making sure to fill out anything marked with FIXME (required) or TODO (usually tips or optional stuff you might want)

• Push your changes! Or at least copy them somewhere if you're on a live medium.

Bootstrapping

To get everything up and running, you need flake-enabled nix and home-manager.

First off, check your nix version using nix --version.

Version < 2.4

Bummer, your nix version does not support flakes. But fear not!

You don't need to mess around with channels to get up and running.

Just run:

nix-shell

Wow, that was easy. Our shell.nix file will detect you can't evaluate (nor lock) the flake, and will grab nix and home-manager from the latest nixos-unstable versions, just for you.

Once you're bootstrapped, remember to run nix flake lock and commit the newly-created flake.lock into your repository, this will make future bootstraps reproductible.

Version >= 2.4

Congrats, your nix version supports flakes! It's just hidden behind a feature flag.

You can bootstrap with:

nix --experimental-features develop "nix-command flakes" .#default

The shell will also enable those experimental features, so no need to pass that argument while you're inside (or after installation, if you set the option that enables them globally).

This should generate a flake.lock. Remember to commit it, as this will make future bootstraps reproductible.

Usage

• Run sudo nixos-rebuild switch --flake .#hostname to apply your system configuration.
  • If you're still on a live installation medium, run nixos-install --flake .#hostname instead, and reboot.
• Run home-manager switch --flake .#username@hostname to apply your home configuration.

And that's it, really! You're ready to have fun with your configurations using the latest and greatest nix3 flake-enabled command UX.

What next?

User password and secrets

For people fresh from installation: Unless you used --no-root-passwd, nixos-install prompted you for a root password. Use it to log into the root account, set your own account's password imperatively with passwd, and disable root login (sudo passwd -l root). You can also use --no-root-passwd and instead set initialPassword for your user, for a temporary password upon install.

If you don't want to set your password imperatively, you can also use passwordFile for safely and declaratively setting a password from a file outside the nix store.

There's also more advanced options for secret management, including some that can include them (encrypted) into your config repo and/or nix store, be sure to check them out if you're interested.

Dotfile management with home-manager

Besides just adding packages to your environment, home-manager can also manage your dotfiles. I strongly recommend you do, it's awesome!

For full nix goodness, check out the home-manager options with man home-configuration.nix. Using them, you'll be able to fully configure any program with nix syntax and its powerful abstractions.

Alternatively, if you're still not ready to rewrite all your configs to nix syntax, there's home-manager options (such as xdg.configFile) for including files from your config repository into your usual dot directories. Add your existing dotfiles to this repo and try it out!

Try opt-in persistance

You might have noticed that there's impurity in your NixOS system, in the form of configuration files and other cruft your system generates when running. What if you change them in a whim to get something working and forget about it? Boom, your system is not fully reproductible anymore.

You can instead fully delete your / and /home on every boot! Nix is okay with a empty root on boot (all you need is /boot and /nix), and will happily reapply your configurations.

There's two main approaches to this: mount a tmpfs (RAM disk) to /, or (using a filesystem such as btrfs or zfs) mount a blank snapshot and reset it on boot.

For stuff that can't be managed through nix (such as games downloaded from steam, or logs), use impermanence for mounting stuff you to keep to a separate partition/volume (such as /nix/persist or /persist). This makes everything vanish by default, and you can keep track of what you specifically asked to be kept.

Here's some awesome blog posts about it:

• Erase your darlings
• Encrypted BTRFS with Opt-In State on NixOS
• NixOS: tmpfs as root and tmpfs as home

Adding custom packages

Something you want to use that's not in nixpkgs yet? You can easily build and iterate on a derivation (package) from this very repository.

Create a folder with the desired name inside pkgs, and add a default.nix file containing a derivation. Be sure to also callPackage them on pkgs/default.nix.

You'll be able to refer to that package from anywhere on your home-manager/nixos configurations, build them with nix build .#package-name, or bring them into your shell with nix shell .#package-name.

See the manual for some tips on how to package stuff.

Adding overlays

Found some outdated package on nixpkgs you need the latest version of? Perhaps you want to apply a patch to fix a behaviour you don't like? Nix makes it easy and manageble with overlays!

Use the overlay/default.nix file for this.

If you're creating patches, you can keep them on the overlay folder as well.

See the wiki article to see how it all works.

Adding your own modules

Got some configurations you want to create an abstraction of? Modules are the answer. These awesome files can expose options and implement configurations based on how the options are set.

Create a file for them on either modules/nixos or modules/home-manager. Be sure to also add them to the listing at modules/nixos/default.nix or modules/home-manager/default.nix.

See the wiki article to learn more about them.

Adding more hosts or users

You can organize them by hostname and username on nixos and home-manager directories, be sure to also add them to flake.nix.

NixOS makes it easy to share common configuration between hosts (you might want to create a common directory for these), while keeping everything in sync. home-manager can help you sync your environment (from editor to WM and everything in between) anywhere you use it. Have fun!