Nix implementation for my Linux laptops, desktops, and homelab servers. Adapted from Misterio77's standard starter config with inspiration from EmergentMind's youtube tutorials, 8bitbuddhism, and many others.

• Nix Ecosystem Terminology
• Nixlab Features
• Implementations
• Repository Layout

Nix Ecosystem Terminology

List of common terms and their definitions (click to expand)

• Nix Language: a domain-specific, declarative, pure, functional, lazy-evaluated, dynamically typed, language
  • Nix values: data types that are immutable, can be whole expressions themselves, are only computed when needed, and type-error detected at evaluation
• Nix Expressions: Nix lang code (functions) that describes how to build packages or configure systems
  • Derivations: the backend build task; specifies all inputs, dependencies, and build steps of an expression
• Nix Packages Collection (Nixpkgs): a large repository of Nix expressions
• Nix Store: complex abstractions of immutable file system data (software packages, dependencies, etc.)
• Nix Package Manager: a command-line toolset, with an atomic update model, that:
  1. evaluates expressions into derivations
  2. builds packages from derivations
  3. manages the Nix Store (handles dependencies, ensures reproducibility), where packages are kept
• NixOS: Linux distro that has a system configuration entirely built with Nix

Nixlab Features

Implimented features and what they do (click to expand)

Contains

• Cachix: cache service of prebuilt binaries; speeds installs, avoids compilations
• Flakes: a schema for writing, referencing, and sharing Nix expressions
  • consists of a filesystem tree with a flake.nix file in root directory; specifies:
    • metadata about the flake
    • inputs (expressions, pkg repos, other flakes) which are taken as dependencies
    • outputs (pkg defs, dev-envs, NixOS configs, modules, etc.) are whatever the flake produces; ultimately given as Nix values, evaluated by the Nix package manager
  • updates Nix package manager's CLI with the new/experimental commands
  • version-pinning of pkgs and dependencies via flake.lock file (increases reproducibity)
• Home Manager: home-directory management module; installs user programs, pkgs, and config files, sets env-variables, dotfiles, and any other arbitrary file
• Modules: to customize options, settings, and functionality in config
  • segregation of system and user level modules, encapsulated by role or function
• Overlays: custom modifications, extensions, and patches of Nixpkgs
• Shells: clean, reproducible, and isolated environments
• Single source of truth: remote nixlab repo is where all systems:
  1. auto-push their updated flakes,
  2. auto-pull any hourly changes, and
  3. rebuild/evaluate from nightly

Aspirational

• Declarative virtualization systems
• Scripting for initial hardware configuration (disko)
• Support for various WMs and desktop environments (KDE, XFCE, and Sway)
• Custom packages and services
• Secret management system
• Impermanent system; declaratively built on boot and connected to storage drives for data persistence

Implementations

Instalation directions and update commands (click to expand)

• Installation:
  1. Install NixOS with appropriate labelled partitions (boot, root, swap, home, shelf)
  2. Mount and setup local repo in new home partition:
     • firstly, nix-shell -p git wget curl,
     • then (in the partition) mkdir -p /temhr,
     • finally cd /temhr && git clone https://github.com/temhr/nixlab.git
  3. First rebuild: sudo nixos-rebuild boot --flake github:temhr/nixlab#[HOSTNAME] --extra-experimental-features "nix-command flakes" && sudo reboot
• Updating systems imperatively:
  • Flakes: $ nix flake update --flake /home/temhr/nixlab
  • NixOS: $ sudo nixos-rebuild switch --flake /home/temhr/nixlab
  • Cachix: $ sudo cachix use [package_name]
  • Shells: $ nix develop /home/temhr/nixlab#<shell-name>

Repository Layout

• bin: various shell scripts
• cachix: prebuilt cached binaries to pull
• hardware: machine level configurations and devices
  • common: machine-agnostic settings and options
    • global: universal to all machines
    • optional: machine selection required
• home: user level configurations (home manager) and files
  • common: user-agnostic settings and options
    • files: various user related files and scripts
    • global: universal to all users
    • optional: user selection required
  • temhr: user-specfic preferences
• hosts: system level configurations and files
  • common: host-agnostic programs, services, users, etc.
    • files: various host related scripts
    • global: universal to all hosts
    • optional: host selection required
• lib: templates and other helper nix-code
• modules: encapsulated packages and persistent applications
  • home-manager: user-relevant modules
  • nixos: system-relevant modules
• overlays: custom overrides and extensions
  • default: repository switching via flags (pkgs.unstable, pkgs.stable)
• pkgs: custom written packages
  • empty
• shells: temporary, isolated, shell environments
• flake.nix: entry point
• flake.lock: version pinner