0007 Use nixos-anywhere for machine deployments

0007 Use nixos-anywhere for machine deployments#

Context and Problem Statement#

The full automation of the cluster deployment does start with installing the base operating system into the machines.

How to automate the machine setup?

Decision Drivers#

  • NixOS shall be used as the base operating system.

  • A machine can be a bare-metal system, a virtual machine or any sort of cloud based machine.

Considered Options#

  • Script the installation steps based on the readme file in /infrastructure/nixos.

  • Expect the base system to be there and start from the k0s deployment.

  • Used a customized installer image and automate from there.

  • Use nixos-anywhere to automatically install the operating system.

Decision Outcome#

nixos-anywhere will be used for the provisioning of the operating system into the given machines.

This is the only option which does provide a realistic chance to have the deployment automated independently of the machine type and with efforts which can currently be handled.

Consequences#

  • Good, because the same automation should work on any machine type.

  • Good, because the existing NixOS machine definitions can be used.

  • Good, because the existing layers like Nix and NixOS still work. Building via nix build stays possible and installing via plain nixos-rebuild switch stays also possible.

  • Good, because the single requirement is to have a reachable machine which supports kexec to boot into a different system.

Pointers#