Can't build nixos configuration using native linux builder

[shishkin]

I have installed determinate nix on darwin using a flake following guidelines from README.

When I build a package like this nix build --system x86_64-linux --option substitute false --option binary-caches "" nixpkgs#legacyPackages.x86_64-linux.jq I get an ELF executable that predictably fails to run on macos.

However when I try to build a nixos configuration from a flake like this: nix build .#nixosConfigurations.myhostname.config.system.build.toplevel I get a bunch of errors like:

error: Cannot build '/nix/store/saypdak2k45zyl5wgbl3lcw5syi30mvg-nixos.conf.drv'.
       Reason: required system or feature not available
       Required system: 'aarch64-linux' with features {}
       Current system: 'aarch64-darwin' with features {apple-virt, benchmark, big-parallel, nixos-test}

The introduction blog mentions external-builders config, but it was disallowed in determinateNix.customSettings.

What am I doing wrong?

[grahamc]

What does determinate-nixd status and determinate-nixd version say?

[shishkin]

❯ determinate-nixd status
Note: Determinate Nix 3.15.2 is now available but you're still running version 3.11.2, which is out of date. Please update Determinate Nix using the command line:

    sudo determinate-nixd upgrade

Or re-run the Determinate package from https://dtr.mn/determinate-nix
For more information, see: https://dtr.mn/update
Authentication: logged-out

~
❯ determinate-nixd version
Determinate Nixd daemon version: 3.11.2
Determinate Nixd client version: 3.11.2
Latest version: 3.15.2

A new version of Determinate Nix is available. Please update Determinate Nix using the command line:

    sudo determinate-nixd upgrade

Or re-run the Determinate package from https://dtr.mn/determinate-nix
For more information, see: https://dtr.mn/update

The following features are enabled:

 * lazy-trees

Visit https://dtr.mn/features for more information.

[shishkin]

I'm surprised that the version is out of date since I've updated the flake just now and switched my local darwin config.

[cpick]

I believe I'm hitting the same issue, except that the first nix build command in the original example fails for me as well:

❯ nix build --system x86_64-linux --option substitute false --option binary-caches "" nixpkgs#legacyPackages.x86_64-linux.jq
warning: ignoring the client-specified setting 'system', because it is a restricted setting and you are not a trusted user
warning: ignoring the client-specified setting 'system', because it is a restricted setting and you are not a trusted user
warning: ignoring the client-specified setting 'system', because it is a restricted setting and you are not a trusted user
error: Cannot build '/nix/store/2kbbzfsz1hzd21yj0h989s3z40cgrp58-stage0-posix-1.9.1-source.drv'.
       Reason: required system or feature not available
       Required system: 'x86_64-linux' with features {}
       Current system: 'aarch64-darwin' with features {apple-virt, benchmark, big-parallel, nixos-test}
....
❌ flake:nixpkgs#legacyPackages.x86_64-linux.jq
error: Build failed due to failed dependency

Based on this output:

❯ determinate-nixd status
[NOTE] Telemetry is disabled, which makes it harder to build great software. We don't collect much, so please turn it back on: https://dtr.mn/telemetry
Authentication: logged-out

❯ determinate-nixd version
[NOTE] Telemetry is disabled, which makes it harder to build great software. We don't collect much, so please turn it back on: https://dtr.mn/telemetry
Determinate Nixd daemon version: 3.16.3
Determinate Nixd client version: 3.16.3

You are running the latest version of Determinate Nix.

The following features are enabled:

 * lazy-trees

Visit https://dtr.mn/features for more information.

I don't see anything about external-builders in that output so I believe the builds are failing because the feature is still experimental and not enabled by default, correct?

I use nix-darwin and so I tried enabling experimental-builders with the following in my modules:

inputs.determinate.darwinModules.default
{
  determinateNix = {
    enable = true;
    customSettings.external-builders = true;
  };
}

However, that last setting causes:

❯ sudo -- darwin-rebuild switch --flake .
building the system configuration...
warning: Git tree '/Users/cpick/src/dotfiles' has uncommitted changes
error:
       … while evaluating the attribute 'optionalValue.value'
         at «github:nixos/nixpkgs/72b1d82»/lib/modules.nix:1298:5:
         1297|
         1298|     optionalValue = if isDefined then { value = mergedValue; } else { };
             |     ^
         1299|   };

       … while evaluating a branch condition
         at «github:nixos/nixpkgs/72b1d82»/lib/modules.nix:1298:21:
         1297|
         1298|     optionalValue = if isDefined then { value = mergedValue; } else { };
             |                     ^
         1299|   };

       … while evaluating definitions from `/nix/store/1clx53qq7lncq97k8bjpx15scv0q749g-source/modules/system':

       (stack trace truncated; use '--show-trace' to show the full, detailed trace)

       error:
       Failed assertions:
       - These settings are not allowed in `determinateNix.customSettings`:
         bash-prompt-prefix, external-builders, extra-nix-path, netrc-file, ssl-cert-file, upgrade-nix-store-path-url

So I believe it needs to be enabled through another mechanism?

[Sped0n]

@cpick you do need to apply on your own, but they respond pretty quickly

https://docs.determinate.systems/determinate-nix/#linux-builder

This feature will gradually be rolled out to Determinate Nix users over the coming weeks and months. If you’re eager to try it out now, contact us at support@determinate.systems to request access and include your FlakeHub user name.