machine_setup/nix/kubernetes/roles/containerd/default.nix

{
  config,
  lib,
  pkgs,
  ...
}:

let
  my-cni-plugins = pkgs.buildEnv {
    name = "my-cni-plugins";
    paths = with pkgs; [
      cni-plugins
      cni-plugin-flannel
    ];
  };
  my-cni-configs = pkgs.callPackage ./package/cni_conf/package.nix { };
in
{
  imports = [ ];

  options.me = {
    containerd.enable = lib.mkOption {
      type = lib.types.bool;
      default = false;
      example = true;
      description = "Whether we want to install containerd.";
    };
  };

  config = lib.mkIf config.me.containerd.enable {
    virtualisation.containerd.enable = true;
    virtualisation.containerd.settings = {
      "plugins" = {
        "io.containerd.grpc.v1.cri" = {
          "cni" = {
            "bin_dir" = "/opt/cni/bin";
            "conf_dir" = "/etc/cni/net.d";
            # "bin_dir" = "${my-cni-plugins}/bin";
            # "conf_dir" = "${my-cni-configs}";
          };
          "containerd" = {
            "default_runtime_name" = "runc";
            "runtimes" = {
              "runc" = {
                "options" = {
                  "SystemdCgroup" = true;
                };
                "runtime_type" = "io.containerd.runc.v2";
              };
            };
            "snapshotter" = "overlayfs";
          };
        };
      };
      "version" = 2;
    };

    systemd.services.containerd.preStart = ''
      ${pkgs.toybox}/bin/install -d -m 0755 /opt/cni/bin /etc/cni/net.d
      ${pkgs.toybox}/bin/install ${my-cni-plugins}/bin/* /opt/cni/bin/
      ${pkgs.toybox}/bin/install ${my-cni-configs}/* /etc/cni/net.d/
      echo "Copied CNI plugins/config."
    '';

    environment.persistence."/persist" = lib.mkIf (config.me.mountPersistence) {
      hideMounts = lib.mkForce false;
      directories = [
        "/var/lib/containerd"
      ];
    };
  };
}