Allow setting of channel host-wide

[ymarkus]

I would like to use this template to manage all my NixOS systems. Right now I can't find a way to do it easily.
Basically, I would like my servers to follow release and my Laptop/PC to follow unstable

Describe alternatives you've considered
Maybe this is possible with an overlay? I'm not that familiar with overlays as I haven't used them much.

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[Pacman99]

I haven't tested this, but lets say you set the nixos input in the flake to be 20.09, which would then be the default.
You can add master to extern/default.nix as a specialArg:

specialArgs = {
  unstableModulesPath = "${master}/nixos/modules";
  hardware = nixos-hardware.nixosModules;
  inherit master;
};

Then in the host file of any server you want to track master entirely:

{ master, ... }:
nixpkgs.pkgs = mkForce master;

mkForce because it is set to pkgs by default in hosts/default.nix

Again I'm not sure if this will work.

I personally just use a separate repo/nixflk for my server. I'm doubt any configuration framework would be able to abstract away the differences between the format and requirements of my laptop and server configs.

[nrdxp]

Flakes don't use or require nix channels, but the 'nixos' flake input is used as the base of the system. So if you want to rebase on unstable, just point the input from 'release-20.09' to 'nixos-unstable' in the uri and you'll be good to go.

The default mechanism for deploying a release while easily overriding packages and modules from master if/where required, is also available to consider.

[ymarkus]

I haven't tested this, but lets say you set the nixos input in the flake to be 20.09, which would then be the default.
You can add master to extern/default.nix as a specialArg:

specialArgs = {
  unstableModulesPath = "${master}/nixos/modules";
  hardware = nixos-hardware.nixosModules;
  inherit master;
};

Then in the host file of any server you want to track master entirely:

{ master, ... }:
nixpkgs.pkgs = mkForce master;

mkForce because it is set to pkgs by default in hosts/default.nix

Again I'm not sure if this will work.

I personally just use a separate repo/nixflk for my server. I'm doubt any configuration framework would be able to abstract away the differences between the format and requirements of my laptop and server configs.

I'm not quite sure if that would work... nix flake uses the pkgs that you input to lib.nixosSystem and this project also pulls in nixos in different places, such as lib/default.
I'd like my user configs to be the same that's why using one project would be better for me.

But thanks, I'll try it out and report back.

[ymarkus]

Flakes don't use or require nix channels, but the 'nixos' flake input is used as the base of the system. So if you want to rebase on unstable, just point the input from 'release-20.09' to 'nixos-unstable' in the uri and you'll be good to go.

The default mechanism for deploying a release while easily overriding packages and modules from master if/where required, is also available to consider.

Thanks, but I understand how to change it for all hosts. My wish would be to use the same flake.nix to deploy some hosts with stable and some with unstable/master (not only the packages, but the modules too). Doing it for every package is a lot of work if I'd like the whole system to use that channel...

[Pacman99]

Yeah that makes sense. Thats what I use the home-manager only configurations for, so I can use my personal nixflk on my server, and just apply the home-manager configs.

But the server specific things are in a different repository.

Not quite sure how to solve your problem though.

[nrdxp]

@ymarkus, sorry, misunderstood the question. I am actually going to be extracting out a lot of the logic in the existing hosts/default to be easily modifiable per host. This will remain open til that's finished.

[ymarkus]

Wow, great! Thank you very much.

[Pacman99]

this is now possible in the develop branch with the channels argument and you can set the channelName for each host. Closing this, re-open if there are any problems with the new feature after the next release.