aynish/nix-starter-configs

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Gabriel Fontes f22eb905f4

improve header hierarchy, add experimental features feature flag

2022-04-24 20:43:29 -03:00

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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). Acessible 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
Clone this repo to somewhere acessible (somewhere in your home directory is good enough)
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)
Create a remote repo (github, gitlab, sr.ht, etc) and push your changes for safekeeping (or at least copy your directory to somewhere safe, specially if you're on a installation 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 develop --experimental-features "nix-command flakes" .#default

The shell will also enable those experimental features, so no need for that argument after entering it.

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. Ignore the home-manager step for now.
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.

Include files using 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 modules with man home-configuration.nix. Using them, you'll be able to fully configure any usual dotfile with nix syntax and abstractions (including your own powerful modules and functions).

Alternatively, if you're still not ready to rewrite all your configs in nix syntax, there's home-manager options (such as xdg.configFile) for including files from your nix-config repository into your config 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? 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, and will happily reapply your configurations (as long as /nix is intact).

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.

Customize your NixOS configuration

Use the nixos/configuration.nix file.

For a list of options, see man configuration.nix. Also see the manual.

Customize your home-manager configuration

Use the home-manager/home.nix file.

For a list of options, see man home-configuration.nix. Also see the manual.

Adding packages

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

See the manual.

Adding overlays

Use the overlay/default.nix file.

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

See the wiki article.

Adding your own modules

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.