Nix

Introduction to Nix

You can find the examples that were presented in https://github.com/ereslibre/nix-demo

Transcript

1. Nix
2. $(who) • Rafael Fernández López (@ereslibre) • Staff Engineer at VMware • Interested in libre software and open knowledge • Went through a number of technologies: ◦ KDE ◦ Ruby on Rails ◦ Docker ◦ Kubernetes ◦ Nix ◦ WebAssembly
3. Problem statement.
4. Software is eating the world.
5. Software has already eaten the world.
6. Multiple times.
7. The problem - closer to the metal • The system is a snowflake composed of manual changes • How to rollback? How to evolve? How to reproduce? • Change something manually in /etc/…, … and restart a service ◦ System upgrades ◦ Chef/Puppet/Salt help a little ◦ Terraform/Packer get closer to immutable infrastructure; still do not solve the whole issue spectrum
8. The problem - containers • Dockerfile; usually a moving target ◦ FROM ubuntu:latest ◦ FROM ubuntu:18.04 • How did we build this container image? Where is the Dockerfile? • Not trivial to write reproducible Dockerfiles ◦ FROM … ◦ RUN … • What do we really want to isolate? ◦ Filesystem, network namespace, PID namespace… • Software supply chain traceability
9. Can we do anything about it?
10. Nix: what is it? • A language
11. Nix: what is it? • A language • A package manager
12. Nix: what is it? • A language • A package manager • A package collection (nixpkgs)
13. Nix: what is it? • A language • A package manager • A package collection (nixpkgs) • A Linux distribution (NixOS)
14. Nix: language • Domain specific • Declarative • Pure • Functional • Lazy • Dynamically typed
15. Nix: package manager • Does not follow the Linux Standard Base (LSB) • Magic sauce: patchelf ◦ Change the dynamic loader (ELF interpreter) of executables ◦ Change/Shrink the RPATH of executables and libraries ◦ Manage dynamic libraries dependencies (add, remove, replace, change SONAME) • Nix store: globally readable nix store
16. Nix: package collection (nixpkgs) • Over 80,000 software packages • Tooling to produce multiple outputs
17. Nix: operating system (NixOS) • Based off nixpkgs • 99.77% of the nixos.iso_minimal.x86_64-linux paths are reproducible • Atomic • Trivial rollback capability • nixos-generators
18. Nix: what are you building? • A derivation • A container image • A machine image ◦ Azure, Digital Ocean, Amazon EC2, Google Compute Engine, Hyper-V, Libvirt, Proxmox, VMware… • Straightforward cross-compilation ◦ Build platform ◦ Host platform ◦ Target platform (only applicable for compilers and similar tools)
19. Nix: a building block • Direnv • Riff ◦ Automatically provide external dependencies for Rust projects (other languages in the future) • nixery.dev • Agenix ◦ Secret management
20. Nix: Flakes • “Experimental” feature (until 3.0?) ◦ Opt-in feature • Concept of Inputs and Outputs • Pinned Inputs • Pure
21. Nix: software as a service • Source distribution ◦ Huge public binary cache • nix build or nix run ◦ A nixpkgs derivation ▪ From “master” ▪ From a specific release ▪ From a specific revision ◦ A third party package • Development shells
22. Nix: extras • Original paper (18 years ago) ◦ Initial release (19 years ago) • Multi-OS, user specific ◦ Home-manager • OS specific ◦ nix-darwin • Deployment ◦ deploy-rs ◦ nix-deploy, nix-delegate ◦ nixery.dev
23. Nix: resources • Documentation • Nix pills • nix.dev • NixOS options • Home Manager options • Nix-Darwin options • Flake documentation • Awesome Nix • Reproducibility: NixOS • Hydra