use-without-flakes.md

Use without flakes

While nixos-anywhere is designed to work optimally with Nix Flakes, it also supports the traditional approach without flakes. This document outlines how to use nixos-anywhere without relying on flakes. You will need to import the disko nixos module in your NixOS configuration and define disko devices as described in the examples.

Generate Required Store Paths

Before you can use nixos-anywhere without flakes, you'll need to manually generate the paths for the NixOS system toplevel and disk image. The paths are generated using nix-build and are necessary for executing nixos-anywhere.

Generating NixOS System Toplevel:

Execute the following command to generate the store path for the NixOS system toplevel:

nix-build -I nixos-config=/etc/nixos/configuration.nix -E '(import <nixpkgs/nixos> {}).config.system.build.toplevel'

This will output a path in /nix/store that corresponds to the system toplevel, which includes all the software and configurations for the system. Make note of this path for later use.

Generating Disk Image without Dependencies:

To generate the disk image without dependencies, execute:

nix-build -I nixos-config=/etc/nixos/configuration.nix -E '(import <nixpkgs/nixos> {}).config.system.build.diskoNoDeps'

This will also output a script path in /nix/store that will format your disk. Keep this path handy as well.

Running NixOS-Anywhere

With both paths in hand, you can execute nixos-anywhere as follows:

nixos-anywhere --store-paths /nix/store/[your-toplevel-path] /nix/store/[your-disk-image-path]

Replace [your-toplevel-path] and [your-disk-image-path] with the corresponding store paths you generated earlier.