nixos container

flake.nix

{
  description = "NixOS container image";

  inputs.nixpkgs.url = "github:nixos/nixpkgs/nixos-25.05";

  outputs = { self, nixpkgs }:
    let
      system = "x86_64-linux";
      pkgs = import nixpkgs { inherit system; };
      lib = nixpkgs.lib;

      osRelease = pkgs.writeTextDir "etc/os-release" ''
        ANSI_COLOR="0;38;2;126;186;228"
        BUG_REPORT_URL="https://github.com/NixOS/nixpkgs/issues"
        BUILD_ID="25.05.20251120.c58bc7f"
        CPE_NAME="cpe:/o:nixos:nixos:25.05"
        DEFAULT_HOSTNAME=nixos
        DOCUMENTATION_URL="https://nixos.org/learn.html"
        HOME_URL="https://nixos.org/"
        ID=nixos
        ID_LIKE=""
        IMAGE_ID=""
        IMAGE_VERSION=""
        LOGO="nix-snowflake"
        NAME=NixOS
        PRETTY_NAME="NixOS 25.05 (Warbler)"
        SUPPORT_END="2025-12-31"
        SUPPORT_URL="https://nixos.org/community.html"
        VARIANT=""
        VARIANT_ID=""
        VENDOR_NAME=NixOS
        VENDOR_URL="https://nixos.org/"
        VERSION="25.05 (Warbler)"
        VERSION_CODENAME=warbler
        VERSION_ID="25.05"
      '';

    in
    {
      packages.${system}.default = pkgs.dockerTools.buildLayeredImage {
        name = "nixos";
        tag = lib.version;

        contents = with pkgs; [
          osRelease

          dockerTools.binSh
          dockerTools.usrBinEnv
          dockerTools.fakeNss
          dockerTools.caCertificates

          bashInteractive
          coreutils
          curl
          findutils
          gitMinimal
          gnugrep
          nix
          vim
        ];

        extraCommands = ''
          mkdir -p root tmp
          chmod 1777 tmp
          chmod 700 root
        '';

        config = {
          Cmd = [ "/bin/bash" ];
          Env = [
            "USER=root"
            "HOME=/root"
            "PATH=/bin:/usr/bin"
            # "SSL_CERT_FILE=/etc/ssl/certs/ca-bundle.crt"
            "LANG=C.UTF-8"
          ];
        };
      };
    };
}

Initial nixos:25.05 container

Assisted by Gemini 3 Pro

$ nix build
$ nix path-info -Sh ./result 
$ cat result | podman load