My NixOS and Home Manager configurations

These configurations can be used differently to manage:

• the current user configuration;
• the system configuration;
• both system and user configurations at the same time.

This repository is hosted in my Gitea server and mirrored to GitHub.

Principles

• NixOS should be easy to reinstall and be ready to use — so that I no longer feel attached to my machines.
• Each host should have its own configuration file inside ./hosts.
• All frequently used boilerplate should be modularized into ./modules so that a computer configuration is always clear and easy to be made intuitively.
• A user should not be forced to use home-manager. Each user is responsible for using the system as wished (imperatively or declaratively).
• Each user should be able to configure their own WM/GE without having to contact the system admin.

Structure

• hosts
  • adam
    • configuration.nix
    • system.nix (TODO better than actual double read?)
    • hardware-config.nix
    • home.nix: extra home-manager base config for this machine
    • secrets.yaml or secrets/*.yaml: machine secrets
• users
  • marcosrdac
    • home.nix: main home-manager user configuration
    • hosts: extra home-manager machine-specific user configurations (for machines that are not mine or are not running NixOS)
    • secrets.yaml or secrets/*.yaml: user secrets
  • guest
  • vim: just an easy to use neovim setup (TODO)
• overlays: i.e.: neovim configs and plugins is an overlay
• modules
  • nixos
  • home-manager
  • common
• .sops.yaml: sets up encryption rules for passwords
• secrets: common passwords

Dependencies

You will need Nix with Flakes enabled to use my configurations, as well as git.

Acquire Flakes

nix-channel --update
nix-env -f '<nixpkgs>' -iA nixUnstable

Requirements software

nix-shell -p wget vim git 
# or use below facilities
nix-shell -p wget vim git screen lf

Current user configuration

Download

git clone https://git.marcosrdac.com/marcosrdac/nixcfg.git $HOME/.config/home-manager

Install

home-manager switch --flake "$HOME/.config/home-manager#$(hostname)-$(whoami)"
# i.e.: if my hostname is `adam` and my username is `marcosrdac`:
#home-manager switch --flake "$HOME/.config/home-manager#adam-marcosrdac"

Observation: host is defined in hosts and my user configurations are defined in users/$USER TODO add a placeholder for non-NixOS machines I might use

System configuration

Clone the repository

As super user:

git clone https://git.marcosrdac.com/marcosrdac/nixcfg.git /etc/nixos

Set the system hostname

Set your hostname: Flakes will use it to setup the correct machine. Example for my adam desktop:

hostname adam

Build system

Then to build the machine for the first time:

nixos-rebuild switch --flake "/etc/nixos#$(hostname)"

Both system and user configuration

Start by configuring the system, then symlink /etc/nixos to /home/$USER/home-manager. Make the user part of nixcfg group in the specific machine configuration, so that it can modify the configuration files without super powers.

ln -s /etc/nixos /home/$USER/.config/home-manager

Now, as a normal user, you can now run similar commands to user install section section's to configure your home space, except that $HOME/.config/home-manager will become its original configuration directory (/etc/nixos):

home-manager switch --flake "/etc/nixos#$(hostname)-$(whoami)"
# i.e.: if my hostname is `adam` and my username is `marcosrdac`:
home-manager switch --flake "/etc/nixos#adam-marcosrdac"

Graphical session architecture

The graphical setup follows the same separation between system and user configuration:

• NixOS provides the graphical infrastructure: display manager, X11 support, Wayland support, DBus, Polkit, XWayland, portals, seat management and generic login sessions.
• Home Manager defines the user's graphical environment: window manager or compositor, bars, launchers, startup programs, keybindings and user session scripts.

The system should not hardcode a user's preferred WM/DE. Instead, it exposes generic session entries:

Display manager
  -> User X11 Session
     -> /home/<user>/.xsession
  -> User Wayland Session
     -> /home/<user>/.wsession

Configuring SSH keys

ssh-keygen -t rsa -b 4096
cat ~/.ssh/id_rsa.pub

Copy cat output and paste it into a new SSH key with

Create new SSH access keys using cat output and entitle it username@hostname, where username and hostname are your current ones.

Moving remote from HTTP to SSH

To see current remotes:

git remote -v

To change to SSH:

git remote set-url origin gitea@git.marcosrdac.com:marcosrdac/nixcfg.git

Configuring git

git config --global user.email "mail@marcosrdac.com"
git config --global user.name "Marcos Conceição"

System maintenance

Remove unused packages (nix)

# remove old home-manager generations
home-manager expire-generations 1d
# tip #1
nix-collect-garbage -d
# tip #2
sudo nix-store --optimise

Troubleshoot

nixos-rebuild swith does nothing

You probably don't have enough RAM. Do the following to swap on file before system build:

SWAP_SIZE_MB=2048
sudo dd if=/dev/zero of=/swapfile bs=1M count=$SWAP_SIZE_MB status=progress
sudo chmod 0600 /swapfile
sudo mkswap -U clear /swapfile
# if above does not work, give partition UUID as argument to -U
#lsblk -f
# copy UUID and run command, i.e.:
#sudo mkswap -U 892b1061-772e-4b48-a2dc-e67cb5b7ebc7 clear /swapfile
sudo swapon /swapfile

Grow partition

AWS

nix-shell -p cloud-utils
lsblk
PARTITION_NUMBER=1
sudo growpart /dev/nvme0n1 $PARTITION_NUMBER

Inspiration

• Pinpox' configurations
• Jordan Isaacs' configurations
• Krutonium's configurations
• Misterio77's configurations

TODO

• ssh agent needed to be turned on???

• Do not install fonts unless needed

• Make options in my home-manager modules (xorg vs wayland, etc).

• Default python env should be easily accessable for data analysis stuff.

• I want to be able to install and use my WM configuration from any computer (use xinit and stuff, instead of xinit-hm).

• redshift

• kopia module

• curupira's nextcloud + gitea

• appearance module: font families (regular, symbol), size -> terminal, bars, themes, etc.

• volume module

Future tips

• avoid monolythic sops secrets files (i.e.: secrets.yaml)

Reading tips

• NixOS modules
• Home-manager module