nix-rosetta-builder

A Rosetta 2-enabled, Apple silicon (macOS/Darwin)-hosted Linux Nix builder.

Runs on aarch64-darwin and builds aarch64-linux (natively) and x86_64-linux (quickly using Rosetta 2).

Features

Advantages over nix-darwin’s built in nix.linux-builder (which is based on pkgs.darwin.linux-builder):

• x86_64-linux support enabled by default and much faster (using Rosetta 2)
• Multi-core by default
• More secure:
  • VM runs with minimum permissions (runs as a non-root/admin/wheel user/service account)
  • VM doesn’t accept remote connections (it binds to the loopback interface (127.0.0.1))
  • VM cannot be impersonated (its private SSH host key is not publicly-known)

nix-darwin flake setup

flake.nix:

{
  description = "Configure macOS using nix-darwin with rosetta-builder";

  inputs = {
    nixpkgs.url = "github:nixos/nixpkgs/nixpkgs-unstable";
    nix-darwin = {
      url = "github:lnl7/nix-darwin";
      inputs.nixpkgs.follows = "nixpkgs";
    };
    nix-rosetta-builder = {
      url = "github:cpick/nix-rosetta-builder";
      inputs.nixpkgs.follows = "nixpkgs";
    };
  };

  outputs = inputs@{ self, nix-darwin, nix-rosetta-builder, nixpkgs }: {
    darwinConfigurations."${hostname}" = nix-darwin.lib.darwinSystem {
      modules = [
        # An existing Linux builder is needed to initially bootstrap `nix-rosetta-builder`.
        # If one isn't already available: comment out the `nix-rosetta-builder` module below,
        # uncomment this `linux-builder` module, and run `darwin-rebuild switch`:
        # { nix.linux-builder.enable = true; }
        # Then: uncomment `nix-rosetta-builder`, remove `linux-builder`, and `darwin-rebuild switch`
        # a second time. Subsequently, `nix-rosetta-builder` can rebuild itself.
        nix-rosetta-builder.darwinModules.default
      ];
    };
  };
}

Uninstall

Remove nix-rosetta-builder from nix-darwin’s flake.nix, darwin-rebuild switch, and then:

sudo rm -r /var/lib/rosetta-builder
sudo dscl . -delete /Users/_rosettabuilder
sudo dscl . -delete /Groups/rosettabuilder

Contributing

Feature requests, bug reports, and pull requests are all welcome.