In reply to @schnecfk:ruhr-uni-bochum.de
Do you want to use a "shim" to populate outputs.colmena from outputs.nixosConfigurations?

iirc Buckley changed the approach for the shim, while I found the following solution.
In the flake.nix, I populate colmena from nixosConfigurations.

      colmena = {
        meta = {
          description = "My personal machines";
          nixpkgs = import nixpkgs {
            system = "x86_64-linux";
            overlays = [ nur.overlay ];
          };
        };

      } // builtins.mapAttrs (name: value: {
        nixpkgs.system = value.config.nixpkgs.system;
        imports = value._module.args.modules;
      }) (self.nixosConfigurations);

But to have the deployment options available (and not conflicting with colmena), I had to add:

        extraModules = [ colmena.nixosModules.deploymentOptions ];

in the nixpkgs.lib.nixosSystem call

iirc Buckley changed the approach for the shim, while I found the following solution.
In the flake.nix, I populate colmena from nixosConfigurations.

      colmena = {
        meta = {
          description = "My personal machines";
          nixpkgs = import nixpkgs {
            system = "x86_64-linux";
            overlays = [ nur.overlay ];
          };
        };

      } // builtins.mapAttrs (name: value: {
        nixpkgs.system = value.config.nixpkgs.system;
        imports = value._module.args.modules;
      }) (self.nixosConfigurations);

But to have the deployment options available (and not conflicting with colmena), I had to add this (note that you'd typically use the argument modules):

        extraModules = [ colmena.nixosModules.deploymentOptions ];

in the nixpkgs.lib.nixosSystem call

Nix itself accepts the option --no-substitute, while colmena's similar option is called --no-substitutes. This is unnecessarily confusing, and renaming the option would resolve this.

Hi. It seems mainstream NixOS is heading toward using nixpkgs.lib.nixosSystem, and standard ways of defining nixos hosts in a flake.nix: https://nixos.wiki/wiki/Flakes#Using_nix_flakes_with_NixOS

Any thoughts on integrating with that world with colmena? I'm keen to keep my configuration as close to "mainstream" as I can, while using remote deploys (some of my hosts are definitely too weak to build themselves).

It seems mainstream NixOS is getting remote deploys too: nixos-rebuild --flake .#mymachine --target-host mymachine-hostname --build-host localhost switch

In reply to @n0emis:noemis.me
Is there a easy way to acces the merged nixos-config, e.g. to build a vm with it (via nixos-rebuild build-vm or something like it)?

Could we have a CLI argument or environment variable to override the deployment.targetUser? Useful in cases where the remote user isn't the same, but someone else might need to use a different username to deploy, so setting it in the Nix configuration isn't helpful.