Error when following "Provisioning remote machines via SSH" on macos

[yasuiniko]

Observations
I've been following the tutorial and everything was able to execute without errors up until I tested the disk layout. Here is the command and the output.

[nix-shell:~/github/remote]$ nix-build -E "((import <nixpkgs> {}).nixos [ ./configuration.nix ]).installTest"
evaluation warning: mdadm: Neither MAILADDR nor PROGRAM has been set. This will cause the `mdmon` service to crash.
error:
       … while evaluating the attribute 'drvPath'
         at /nix/store/iwngzlahnbc2xxq0vrx6zdgb8ip23p53-source/lib/customisation.nix:418:7:
          417|     // {
          418|       drvPath =
             |       ^
          419|         assert condition;

       … while calling the 'derivationStrict' builtin
         at <nix/derivation-internal.nix>:37:12:
           36|
           37|   strict = derivationStrict drvAttrs;
             |            ^
           38|

       … while evaluating the option `testScriptString':

       … while evaluating definitions from `/nix/store/iwngzlahnbc2xxq0vrx6zdgb8ip23p53-source/nixos/lib/testing/testScript.nix':

       … while evaluating definitions from `makeTest parameters':

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

       error: Package ‘OVMF-202411’ in /nix/store/iwngzlahnbc2xxq0vrx6zdgb8ip23p53-source/pkgs/applications/virtualization/OVMF/default.nix:269 is marked as broken, refusing to evaluate.

       a) To temporarily allow broken packages, you can use an environment variable
          for a single invocation of the nix tools.

            $ export NIXPKGS_ALLOW_BROKEN=1

          Note: When using `nix shell`, `nix build`, `nix develop`, etc with a flake,
                then pass `--impure` in order to allow use of environment variables.

       b) For `nixos-rebuild` you can set
         { nixpkgs.config.allowBroken = true; }
       in configuration.nix to override this.

       c) For `nix-env`, `nix-build`, `nix-shell` or any other Nix command you can add
         { allowBroken = true; }
       to ~/.config/nixpkgs/config.nix.

Problem
There seems to be an issue with ‘OVMF-202411’ being marked as broken.

Approaches
I don't know how to troubleshoot this as I am new to nix. However I did run the following, to no apparent effect.

nix-channel --add https://nixos.org/channels/nixos-24.05 nixos
nix-channel --update

I also noticed that mynixos.com lists OVMF as "not broken". I wasn't able to find any references to the specific version ‘OVMF-202411’ via google or the in default.nix file listed in the error message.

Willing to help?
I'm happy to help if there's anything I can do.

Priorities

Add 👍 to issues you find important.

[fricklerhandwerk]

Thanks for the report, I can reduce this to

git clone https://github.com/nixos/nixpkgs --depth 1
cd nixpkgs
nix-build -A OVMF --system aarch64-darwin

But the other systems work fine. As a workaround, could you try running your command with --system x86_64-darwin appended? This should Just Work since M* machines have x86 emulators, but no promises since I can't currently test this.

It's a bit unfortunate that Nixpkgs doesn't say why a package broken, and NixOS/rfcs#127 is not rolled out widely. And it's very unfortunate that the underlying issue is a tangle of deeply architectural ones (the system parameter is used for evaluation regardless of compilation target, package evaluation fails eagerly due to assertions) and I hope one of the first items the new @NixOS/stdenv will take a look at.

[RossComputerGuy]

Working as intended: https://github.com/NixOS/nixpkgs/blob/nixos-24.11/pkgs/applications/virtualization/OVMF/default.nix#L277

[yasuiniko]

Ah thank you Ross, I don't know how I missed that.

Frickler, I tried appending --system x86_64-darwin. The build continued to fail, as expected from Ross's link:

.../OVMF/default.nix
broken = stdenv.hostPlatform.isDarwin && stdenv.hostPlatform.isAarch64;

For my part I will just continue with the tutorial and assume that the provided config will work on my target linux machine. Thanks for the help!