Helm and Helmfile

HELM and HELMFILE

Using Helm and Helmfile on NixOS effectivly requires some minor setup.

HELM

The derivation for helm is in nixpkgs und the name kubernetes-helm. However it does not include any plugins for helm.

To see which plugins are avaiable in nixpkgs do a nix search nixpkgs kubernetes-helmPlugins.

In order to make any plugins available to helm itself, nixpkgs provides a helper function called wrapHelm. This allows you to set an attribute called plugins.

The following snippet will give you access to helm with four plugins via your list of system packages. It assumes that you are using nixpkgs as pkgs:

{
  environment.systemPackages = with pkgs; [
      (wrapHelm kubernetes-helm {
        plugins = with pkgs.kubernetes-helmPlugins; [
          helm-secrets
          helm-diff
          helm-s3
          helm-git
        ];
      }) 
    ];
}

Alternatively a self-contained flake for a development shell with helm and plugins available might look like this:

{
  description = "Nix flake for Helm";
  inputs.nixpkgs.url = "github:NixOS/nixpkgs/master";
  inputs.flake-utils.url = "github:numtide/flake-utils";

  outputs = { self, nixpkgs, flake-utils }:
    flake-utils.lib.eachDefaultSystem (system:
      let pkgs = nixpkgs.legacyPackages.${system}; in
      {
        devShells.default = pkgs.mkShell {
          name = "helm devShell";
          nativeBuildInputs = [ pkgs.bashInteractive ];
          buildInputs = with pkgs; [
            (wrapHelm kubernetes-helm {
              plugins = with pkgs.kubernetes-helmPlugins; [
                helm-diff
                helm-secrets
                helm-s3
              ];
            })
          ];
        };
      });
}

Create a flake.nix in some empty directory, paste the snippet above and run it with nix develop

This will create a devShell with helm and listed plugins available. Check helm plugin list to verify.

HELMFILE

Helmfile can be found in nixpkgs as helmfile.

In order to work properly, helmfile requires access to a number of helm plugins aside from the helm binary itself. In version 0.146.0, helmfile has introduced a check for plugin versions which uses helm's Go API directly instead of calling the helm binary. In order to make plugins avaiable after this change, the nix derivation kubernetes-helm-wrapped exposes an attribute called pluginsDir if helm is wrapped with plugins. The helmfile binary needs to be wrapped in turn in order to have access to this attribute.

There are several ways to achieve this. One is using an overlay inside a flake to populate the pluginsDir attribute.

{
  description = "Nix flake for Helm and Helmfile with plugins";
  inputs.nixpkgs.url = "github:NixOS/nixpkgs/master";
  inputs.flake-utils.url = "github:numtide/flake-utils";

  outputs = { self, nixpkgs, flake-utils }:
    flake-utils.lib.eachDefaultSystem (system:
      let
        pkgs = import nixpkgs {
          system = "x86_64-linux";
          overlays = [
            (final: prev: rec {
              kubernetes-helm-wrapped = prev.wrapHelm prev.kubernetes-helm {
                plugins = with prev.kubernetes-helmPlugins; [
                  helm-diff
                  helm-secrets
                  helm-s3
                ];
              };
            })
          ];
        };
      in
      {
        devShells.default = pkgs.mkShell {
          name = "helmfile devShell";
          nativeBuildInputs = with pkgs; [
            bashInteractive
          ];
          buildInputs = with pkgs; [
            kubernetes-helm-wrapped
            helmfile-wrapped
          ];
        };
      });
}

Here helmfile-wrapped reads kubernetes-helm-wrapped.passthru.pluginsDir and picks up the plugins correctly.

Again, create a flake.nix in some empty directory, paste the snippet above and run it with nix develop

This time it will create a devShell with helm and helmfile and listed plugins available. Check helm plugin list to verify for helm. Likewise check helmfile init to see if helmfile finds its helm plugin dependencies.

---

Another approach is via a let ... in block in your configuration.nix.

{ config, pkgs, ... }:
let
  my-kubernetes-helm = with pkgs; wrapHelm kubernetes-helm {
    plugins = with pkgs.kubernetes-helmPlugins; [
      helm-secrets
      helm-diff
      helm-s3
      helm-git
    ];
  };

  my-helmfile = pkgs.helmfile-wrapped.override {
    inherit (my-kubernetes-helm) pluginsDir;
  };
in

{
  environment.systemPackages =  [
    my-kubernetes-helm
    my-helmfile
  ];
}

Create a new *.nix file for the code snippet and import it into your system configuration.nix. In this case it should make helm and helmfile with plugins available to your system.

References

Issue #217768: helmfile does not recognize helm plugins NixOS Discourse: Helm plugin install