SelfHostBlocks cannot be deployed from macOS (aarch64-darwin) to Linux servers (x86_64-linux) using deploy-rs due to flake evaluation requiring x86_64-linux during the local evaluation phase.

[nikhilmaddirala]

Summary

SelfHostBlocks cannot be deployed from macOS (aarch64-darwin) to Linux servers (x86_64-linux) using deploy-rs due to flake evaluation requiring x86_64-linux during the local evaluation phase.

Environment

• Host System: macOS (aarch64-darwin) - Apple Silicon Mac
• Target System: Linux server (x86_64-linux)
• Deployment Tool: deploy-rs with remoteBuild = true
• SelfHostBlocks Version: Latest (commit c9ee41b1d413b460bd652845484c1b1338b8ce5c)

Expected Behavior

Should be able to deploy SelfHostBlocks from macOS to Linux server using deploy-rs with remote building, similar to how regular nixpkgs configurations work.

Actual Behavior

Deployment fails during flake evaluation phase with cross-compilation error:

error: a 'x86_64-linux' with features {} is required to build '/nix/store/cpyipkyc9hy21d7i59k7xsy1f93l00aq-nixpkgs-patched.drv', but I am a 'aarch64-darwin' with features {apple-virt, benchmark, big-parallel, nixos-test}

Reproduction Steps

1. Create flake on macOS using selfhostblocks:

{
  inputs = {
    selfhostblocks.url = "github:ibizaman/selfhostblocks";
    # ... other inputs
  };
  
  outputs = inputs: {
    nixosConfigurations.myserver = inputs.selfhostblocks.lib.x86_64-linux.patchedNixpkgs.lib.nixosSystem {
      system = "x86_64-linux";
      modules = [
        inputs.selfhostblocks.nixosModules.x86_64-linux.default
        # ... configuration modules
      ];
    };
    
    deploy.nodes.myserver = {
      hostname = "example.com";
      remoteBuild = true;  # This doesn't help with evaluation
      # ... deploy config
    };
  };
}

2. Attempt deployment:

nix run github:serokell/deploy-rs .#myserver

3. Error occurs during evaluation phase before any remote operations

Root Cause Analysis (warning: AI generated)

The issue occurs because:

1. SelfHostBlocks uses patched nixpkgs that requires x86_64-linux evaluation
2. deploy-rs evaluates flakes locally before sending to remote system
3. Patched nixpkgs evaluation fails on macOS during this local evaluation phase
4. Remote building doesn't help because evaluation happens before building

[nikhilmaddirala]

Seems similar to: https://github.com/ibizaman/skarabox/issues/90

[ibizaman]

FWIW with the following config and using nix-darwin, I can build it:

      nix.distributedBuilds = true;
      nix.linux-builder = {
        enable = true;
        ephemeral = true;
        maxJobs = 4;
        supportedFeatures = [ "kvm" "benchmark" "big-parallel" "nixos-test" ];
        systems = [
          # "x86_64-linux"
          "aarch64-linux"
        ];
        config = {
          virtualisation = {
            darwin-builder = {
              diskSize = 40 * 1024;
              memorySize = 8 * 1024;
            };
            cores = 6;
          };
        };
      };

      nix-rosetta-builder = {
        enable = true;
        # onDemand = true;
      };

[nikhilmaddirala]

FWIW with the following config and using nix-darwin, I can build it:

      nix.distributedBuilds = true;
      nix.linux-builder = {
        enable = true;
        ephemeral = true;
        maxJobs = 4;
        supportedFeatures = [ "kvm" "benchmark" "big-parallel" "nixos-test" ];
        systems = [
          # "x86_64-linux"
          "aarch64-linux"
        ];
        config = {
          virtualisation = {
            darwin-builder = {
              diskSize = 40 * 1024;
              memorySize = 8 * 1024;
            };
            cores = 6;
          };
        };
      };

      nix-rosetta-builder = {
        enable = true;
        # onDemand = true;
      };

Thanks! Could you try to repro with remote builder via deploy-rs instead of Rosetta builder?

Unfortunately I can't repro what you did due to unrelated issues preventing me from using linux-builder on my darwin machine.