Multi-Architecture Deployments

You can deploy to hosts running different architectures with a single configuration. This requires you to either set up remote builders running the foreign architecture(s), or set up binfmt emulation on the host running Colmena.

binfmt Emulation

This following example sets up binfmt, allowing an X86-64 host (laptop) to build derivations for an AArch64 host (rpi) through QEMU:

{
  # The NixOS machine you are running Colmena on (x86_64-linux)
  laptop = { pkgs, ... }: {
    # Enable binfmt emulation for aarch64-linux
    boot.binfmt.emulatedSystems = [ "aarch64-linux" ];

    # ... Rest of configuration ...
  };

  # The remote machine running a foreign architecture (aarch64-linux)
  rpi = { pkgs, ... }: {
    # Override nixpkgs architecture
    nixpkgs.system = "aarch64-linux";

    # ... Rest of configuration ...
  };
}

(For Flake users, the above attribute set is the value of outputs.colmena)

First, deploy the local configuration with colmena apply-local --sudo. For more information on what is required on the local system, see Local Deployment.

After the new configuration is activated, binfmt emulation will be set up on the local machine. You can then deploy to the rpi node with colmena apply --on rpi.