.github/copilot-instructions.md

@@ -26,8 +26,9 @@ This is a **NixOS system configuration repository** that uses:
 - **`flake.nix`**: Entry point - inputs and outputs only
 - **`inventory.nix`**: Fleet definitions - host configurations
 - **`users.nix`**: User account definitions
-- **`hosts/`**: Host generation logic and hardware types
-- **`sw/`**: Software configurations organized by system type
+- **`variants/`**: Hardware type modules (desktop, laptop, surface, lxc, wsl, etc.)
+- **`glue/`**: Fleet generation logic and common system configuration
+- **`sw/`**: Software configurations by system type
 - **`installer/`**: Build artifact generation (ISO, LXC, etc.)
 - **`templates/`**: Templates for external configurations
 

README.md

@@ -54,18 +54,21 @@ users.nix                 # User account definitions
 
 flake.lock                # Locked dependency versions
 
-hosts/                    # Host generation logic
-├── default.nix           # Main host generator
+variants/                 # Hardware type modules (exportable as nixosModules)
+├── default.nix           # Auto-exports all variant types
+├── nix-desktop.nix       # Desktop workstations
+├── nix-laptop.nix        # Laptop systems
+├── nix-surface.nix       # Surface Pro tablets
+├── nix-lxc.nix           # LXC containers
+├── nix-wsl.nix           # WSL instances
+├── nix-zima.nix          # ZimaBoard systems
+└── nix-ephemeral.nix     # Diskless/netboot systems
+
+glue/                     # Fleet generation and common configuration
+├── fleet.nix             # Processes inventory.nix to generate all hosts
+├── common.nix            # Common NixOS configuration (all hosts)
 ├── boot.nix              # Boot and filesystem configuration
-├── common.nix            # Common system configuration
-├── user-config.nix       # User configuration integration
-└── types/                # Hardware type modules
-    ├── nix-desktop.nix
-    ├── nix-laptop.nix
-    ├── nix-surface.nix
-    ├── nix-lxc.nix
-    ├── nix-wsl.nix
-    └── nix-ephemeral.nix
+└── user-config.nix       # User account and home-manager integration
 
 sw/                       # Software configurations by system type
 ├── default.nix           # Software module entry point

docs/DEVELOPMENT.md

@@ -87,7 +87,7 @@ athenix.users.newuser = {
 };
 ```
 
-2. Enable on hosts in `inventory.nix`:
+2. Enable on fleet in `inventory.nix`:
 
 ```nix
 nix-laptop = {
@@ -294,7 +294,7 @@ For system config:
 ```nix
 # inventory.nix
 nix-lxc = {
-  devices."server" = builtins.fetchGit {
+  devices."server".external = builtins.fetchGit {
     url = "https://git.factory.uga.edu/org/server-config";
     rev = "abc123...";
   };

docs/EXTERNAL_MODULES.md

@@ -28,26 +28,42 @@ External system modules provide host-specific NixOS configurations.
 
 ### Usage
 
-In `inventory.nix`, reference an external module as a device:
+In `inventory.nix`, reference an external module using the `external` field:
 
 ```nix
 nix-lxc = {
   devices = {
-    # Inline configuration
+    # Inline configuration (traditional method)
     "local-server" = {
       athenix.sw.type = "headless";
       services.nginx.enable = true;
     };
     
-    # External module
-    "remote-server" = builtins.fetchGit {
+    # External module (lazy evaluation - fetched only when building this host)
+    "remote-server".external = builtins.fetchGit {
       url = "https://git.factory.uga.edu/org/server-config";
       rev = "abc123def456...";  # Must pin to specific commit
     };
+    
+    # External module with additional local config
+    "mixed-server" = {
+      external = builtins.fetchGit {
+        url = "https://git.factory.uga.edu/org/server-config";
+        rev = "abc123def456...";
+      };
+      # Additional local overrides
+      athenix.users.admin.enable = true;
+      services.openssh.permitRootLogin = "no";
+    };
   };
 };
 ```
 
+**Key Features:**
+- **Lazy Evaluation**: External modules are only fetched when building the specific host
+- **Efficient Rebuilds**: Other hosts can be rebuilt without fetching unrelated external modules
+- **Submodule Support**: Works with Git submodules without affecting other hosts
+
 ### Repository Structure
 
 ```
@@ -99,8 +115,8 @@ server-config/
 
 When a host is built, modules load in this order:
 
-1. Hardware type module (from `hosts/types/nix-*.nix`)
-2. Host common configuration (from `hosts/common.nix`)
+1. Hardware type module (from `variants/nix-*.nix`)
+2. Common system configuration (from `glue/common.nix`)
 3. Software type module (from `sw/{type}/`)
 4. User NixOS modules (from `users.nix` - `nixos.nix` files)
 5. Device-specific overrides (from `inventory.nix`)

docs/INVENTORY.md

@@ -123,11 +123,11 @@ nix-surface = {
 
 ### Method 4: External Module
 
-Reference a Git repository instead of inline configuration:
+Reference a Git repository using the `external` field (lazy evaluation):
 
 ```nix
 nix-lxc = {
-  devices."builder" = builtins.fetchGit {
+  devices."builder".external = builtins.fetchGit {
     url = "https://git.factory.uga.edu/org/builder-config";
     rev = "abc123...";
   };

flake.nix

@@ -69,10 +69,10 @@
       ...
     }:
     let
-      hosts = import ./hosts { inherit inputs; };
+      fleet = import ./glue/fleet.nix { inherit inputs; };
       linuxSystem = "x86_64-linux";
       artifacts = import ./installer/artifacts.nix {
-        inherit inputs hosts self;
+        inherit inputs fleet self;
         system = linuxSystem;
       };
       forAllSystems = nixpkgs.lib.genAttrs [
@@ -86,13 +86,13 @@
       # Formatter for 'nix fmt'
       formatter = forAllSystems (system: nixpkgs.legacyPackages.${system}.nixfmt-rfc-style);
 
-      # Generate NixOS configurations from hosts/default.nix
-      nixosConfigurations = hosts.nixosConfigurations;
+      # Generate NixOS configurations from fleet generator
+      nixosConfigurations = fleet.nixosConfigurations;
 
       # Expose artifacts to all systems, but they are always built for x86_64-linux
       packages = forAllSystems (_: artifacts);
 
-      # Expose modules for external use
+      # Expose host type modules and installer modules for external use
       nixosModules = import ./installer/modules.nix { inherit inputs; };
 
       # Templates for external configurations

glue/boot.nix

@@ -0,0 +1,137 @@
+# ============================================================================
+# Boot & Storage Configuration
+# ============================================================================
+# This module defines:
+# - Disko partition layout (EFI, swap, root)
+# - Bootloader configuration (systemd-boot with Plymouth)
+# - Filesystem options (device, swap size)
+# - Build method options (used by installer/artifacts.nix)
+# - Convenience options (forUser, useHostPrefix)
+
+{ config, lib, ... }:
+
+{
+  options.athenix = {
+    host = {
+      useHostPrefix = lib.mkOption {
+        type = lib.types.bool;
+        default = true;
+        description = "Whether to prepend the host prefix to the hostname (used in inventory and hosts/default.nix).";
+      };
+      filesystem = {
+        device = lib.mkOption {
+          type = lib.types.str;
+          description = "The main disk device to use for installation.";
+        };
+        useSwap = lib.mkOption {
+          type = lib.types.bool;
+          default = true;
+          description = "Whether to create and use a swap partition.";
+        };
+        swapSize = lib.mkOption {
+          type = lib.types.str;
+          description = "The size of the swap partition.";
+        };
+      };
+    };
+  };
+
+  config = {
+    # ========== Disk Partitioning (Disko) ==========
+    disko.enableConfig = lib.mkDefault true;
+
+    disko.devices = {
+      disk.main = {
+        type = "disk";
+        device = config.athenix.host.filesystem.device;
+        content = {
+          type = "gpt";
+          partitions = {
+            # EFI System Partition
+            ESP = {
+              name = "ESP";
+              label = "BOOT";
+              size = "1G";
+              type = "EF00";
+              content = {
+                type = "filesystem";
+                format = "vfat";
+                mountpoint = "/boot";
+                mountOptions = [ "umask=0077" ];
+                extraArgs = [
+                  "-n"
+                  "BOOT"
+                ];
+              };
+            };
+
+            # Swap Partition (size configurable per host)
+            swap = lib.mkIf config.athenix.host.filesystem.useSwap {
+              name = "swap";
+              label = "swap";
+              size = config.athenix.host.filesystem.swapSize;
+              content = {
+                type = "swap";
+              };
+            };
+
+            # Root Partition (takes remaining space)
+            root = {
+              name = "root";
+              label = "root";
+              size = "100%";
+              content = {
+                type = "filesystem";
+                format = "ext4";
+                mountpoint = "/";
+                extraArgs = [
+                  "-L"
+                  "ROOT"
+                ];
+              };
+            };
+          };
+        };
+      };
+    };
+
+    # Bootloader Configuration
+    boot = {
+      loader.systemd-boot.enable = true;
+      loader.efi.canTouchEfiVariables = true;
+      plymouth.enable = true;
+
+      # Enable "Silent boot"
+      consoleLogLevel = 3;
+      initrd.verbose = false;
+
+      # Hide the OS choice for bootloaders.
+      # It's still possible to open the bootloader list by pressing any key
+      # It will just not appear on screen unless a key is pressed
+      loader.timeout = lib.mkDefault 0;
+    };
+
+    # Set your time zone.
+    time.timeZone = "America/New_York";
+
+    # Select internationalisation properties.
+    i18n.defaultLocale = "en_US.UTF-8";
+
+    i18n.extraLocaleSettings = {
+      LC_ADDRESS = "en_US.UTF-8";
+      LC_IDENTIFICATION = "en_US.UTF-8";
+      LC_MEASUREMENT = "en_US.UTF-8";
+      LC_MONETARY = "en_US.UTF-8";
+      LC_NAME = "en_US.UTF-8";
+      LC_NUMERIC = "en_US.UTF-8";
+      LC_PAPER = "en_US.UTF-8";
+      LC_TELEPHONE = "en_US.UTF-8";
+      LC_TIME = "en_US.UTF-8";
+    };
+
+    systemd.sleep.extraConfig = ''
+      SuspendState=freeze
+      HibernateDelaySec=2h
+    '';
+  };
+}

glue/common.nix

@@ -0,0 +1,99 @@
+# ============================================================================
+# Common Host Module
+# ============================================================================
+# This module contains all the common configuration shared by all host types.
+# It is automatically imported by the fleet generator for every host.
+
+{ inputs }:
+{
+  config,
+  lib,
+  ...
+}:
+{
+  imports = [
+    ./boot.nix
+    ./user-config.nix
+    ../sw
+    ../users.nix
+    inputs.home-manager.nixosModules.home-manager
+    inputs.agenix.nixosModules.default
+    inputs.disko.nixosModules.disko
+  ];
+
+  # Define garbage collection options here since they're consumed in this module
+  options.athenix = {
+    forUser = lib.mkOption {
+      type = lib.types.nullOr lib.types.str;
+      default = null;
+      description = ''
+        Convenience option to configure a host for a specific user.
+        Automatically enables the user (sets athenix.users.username.enable = true).
+        Value should be a username from athenix.users.accounts.
+      '';
+    };
+
+    system.gc = {
+      enable = lib.mkOption {
+        type = lib.types.bool;
+        default = true;
+        description = "Whether to enable automatic garbage collection.";
+      };
+      frequency = lib.mkOption {
+        type = lib.types.str;
+        default = "weekly";
+        description = "How often to run garbage collection (systemd timer format).";
+      };
+      retentionDays = lib.mkOption {
+        type = lib.types.int;
+        default = 30;
+        description = "Number of days to keep old generations before deletion.";
+      };
+      optimise = lib.mkOption {
+        type = lib.types.bool;
+        default = true;
+        description = "Whether to automatically optimize the Nix store.";
+      };
+    };
+
+    host.buildMethods = lib.mkOption {
+      type = lib.types.listOf lib.types.str;
+      default = [ "installer-iso" ];
+      description = ''
+        List of allowed build methods for this host (used by installer/artifacts.nix).
+        Supported methods:
+        - "installer-iso": Generates an auto-install ISO that installs this configuration to disk.
+        - "iso": Generates a live ISO (using nixos-generators).
+        - "ipxe": Generates iPXE netboot artifacts (kernel, initrd, script).
+        - "lxc": Generates an LXC container tarball.
+        - "proxmox": Generates a Proxmox VMA archive.
+      '';
+    };
+  };
+
+  config = lib.mkMerge [
+    # Enable forUser if specified
+    (lib.mkIf (config.athenix.forUser != null) {
+      athenix.users.${config.athenix.forUser}.enable = true;
+    })
+
+    {
+      system.stateVersion = "25.11";
+
+      nix.settings.experimental-features = [
+        "nix-command"
+        "flakes"
+      ];
+
+      # Automatic Garbage Collection
+      nix.gc = lib.mkIf config.athenix.system.gc.enable {
+        automatic = true;
+        dates = config.athenix.system.gc.frequency;
+        options = "--delete-older-than ${toString config.athenix.system.gc.retentionDays}d";
+      };
+
+      # Optimize storage
+      nix.optimise.automatic = config.athenix.system.gc.optimise;
+    }
+  ];
+}

glue/fleet.nix

@@ -1,36 +1,23 @@
 {
   inputs,
-  hosts ? import ../inventory.nix,
+  fleet ? import ../inventory.nix,
   ...
 }:
 
 # ============================================================================
-# Host Generator
+# Fleet Generator
 # ============================================================================
 # This file contains the logic to generate NixOS configurations for all hosts
 # defined in inventory.nix. It supports both hostname-based and count-based
 # configurations with flexible type associations.
-#
-# Inventory format:
-# {
-#   "my-hostname" = {
-#     type = "nix-desktop";  # Host type module to use
-#     system = "x86_64-linux";  # Optional
-#     # ... any athenix.* options or device-specific config
-#   };
-#
-#   "lab-prefix" = {
-#     type = "nix-laptop";
-#     count = 5;  # Generates lab-prefix1, lab-prefix2, ... lab-prefix5
-#     devices = {
-#       "machine-1" = { ... };  # Override for lab-prefix1
-#     };
-#   };
-# }
 
 let
   nixpkgs = inputs.nixpkgs;
   lib = nixpkgs.lib;
+
+  # Load all available host types from hosts/
+  hostTypes = import ../variants { inherit inputs; };
+
   # Helper to create a single NixOS system configuration
   mkHost =
     {
@@ -38,9 +25,28 @@ let
       system ? "x86_64-linux",
       hostType,
       configOverrides ? { },
-      externalModulePath ? null,
+      externalModuleThunk ? null,
     }:
     let
+      # Lazy evaluation: only fetch external module when building this host
+      externalModulePath =
+        if externalModuleThunk != null then
+          let
+            # Force evaluation of the thunk (fetchGit, fetchTarball, etc.)
+            fetchedPath = externalModuleThunk;
+            # Extract outPath from fetchGit/fetchTarball results
+            extractedPath =
+              if builtins.isAttrs fetchedPath && fetchedPath ? outPath then fetchedPath.outPath else fetchedPath;
+          in
+          if builtins.isPath extractedPath then
+            extractedPath + "/default.nix"
+          else if lib.isDerivation extractedPath then
+            extractedPath + "/default.nix"
+          else
+            extractedPath + "/default.nix"
+        else
+          null;
+
       # Load users.nix to find external user modules
       pkgs = nixpkgs.legacyPackages.${system};
       usersData = import ../users.nix { inherit pkgs; };
@@ -94,13 +100,10 @@ let
         }
       ) userNixosModulePaths;
 
-      # Load the host type module
-      typeFile = ./types + "/${hostType}.nix";
+      # Get the host type module from the hostTypes attribute set
       typeModule =
-        if builtins.pathExists typeFile then
-          import typeFile { inherit inputs; }
-        else
-          throw "Host type '${hostType}' not found in hosts/types/";
+        hostTypes.${hostType}
+          or (throw "Host type '${hostType}' not found. Available types: ${lib.concatStringsSep ", " (lib.attrNames hostTypes)}");
 
       # External module from fetchGit/fetchurl
       externalPathModule =
@@ -132,6 +135,7 @@ let
       allModules =
         userNixosModules
         ++ [
+          (import ./common.nix { inherit inputs; })
           typeModule
           overrideModule
           { networking.hostName = hostName; }
@@ -192,48 +196,22 @@ let
         lib.mapAttrsToList (
           deviceKey: deviceConfig:
           let
-            # Check if deviceConfig is a path/derivation (from fetchGit, fetchurl, etc.)
-            # fetchGit/fetchTarball return an attrset with outPath attribute
-            isExternalModule =
-              (builtins.isPath deviceConfig)
-              || (builtins.isString deviceConfig && lib.hasPrefix "/" deviceConfig)
-              || (lib.isDerivation deviceConfig)
-              || (builtins.isAttrs deviceConfig && deviceConfig ? outPath);
+            # Check if deviceConfig has an 'external' field for lazy evaluation
+            hasExternalField = builtins.isAttrs deviceConfig && deviceConfig ? external;
 
-            # Extract the actual path from fetchGit/fetchTarball results
-            extractedPath =
-              if builtins.isAttrs deviceConfig && deviceConfig ? outPath then
-                deviceConfig.outPath
-              else
-                deviceConfig;
+            # Extract external module thunk if present (don't evaluate yet!)
+            externalModuleThunk = if hasExternalField then deviceConfig.external else null;
 
-            # If external module, we use base config + overrides as the config
-            # and pass the module path separately
-            actualConfig =
-              if isExternalModule then (lib.recursiveUpdate baseConfig overrides) else deviceConfig;
+            # Remove 'external' from config to avoid conflicts
+            cleanDeviceConfig =
+              if hasExternalField then lib.removeAttrs deviceConfig [ "external" ] else deviceConfig;
 
-            # Merge: base config -> overrides -> device-specific config (only if not external module)
-            mergedConfig =
-              if isExternalModule then
-                actualConfig
-              else
-                lib.recursiveUpdate (lib.recursiveUpdate baseConfig overrides) deviceConfig;
+            # Merge: base config -> overrides -> device-specific config
+            mergedConfig = lib.recursiveUpdate (lib.recursiveUpdate baseConfig overrides) cleanDeviceConfig;
 
             # Check useHostPrefix from the merged config
             usePrefix = mergedConfig.athenix.host.useHostPrefix or true;
             hostName = mkHostName prefix deviceKey usePrefix;
-
-            # If external module, also add a default.nix path for import
-            externalModulePath =
-              if isExternalModule then
-                if builtins.isPath extractedPath then
-                  extractedPath + "/default.nix"
-                else if lib.isDerivation extractedPath then
-                  extractedPath + "/default.nix"
-                else
-                  extractedPath + "/default.nix"
-              else
-                null;
           in
           {
             name = hostName;
@@ -242,7 +220,7 @@ let
                 hostName
                 system
                 hostType
-                externalModulePath
+                externalModuleThunk
                 ;
               configOverrides = mergedConfig;
             };
@@ -289,7 +267,7 @@ let
           { };
     in
     lib.recursiveUpdate deviceHosts countHosts
-  ) hosts;
+  ) fleet;
 
   # Flatten the nested structure
   allHosts = lib.foldl' lib.recursiveUpdate { } (lib.attrValues processInventory);

hosts/boot.nix

@@ -1,194 +0,0 @@
-# ============================================================================
-# Boot & Storage Configuration
-# ============================================================================
-# This module defines:
-# - Disko partition layout (EFI, swap, root)
-# - Bootloader configuration (systemd-boot with Plymouth)
-# - Filesystem options (device, swap size)
-# - Build method options (ISO, iPXE, LXC, Proxmox)
-# - Garbage collection settings
-# - Convenience options (forUser, useHostPrefix)
-
-{ config, lib, ... }:
-
-{
-  options.athenix = {
-    forUser = lib.mkOption {
-      type = lib.types.nullOr lib.types.str;
-      default = null;
-      description = ''
-        Convenience option to configure a host for a specific user.
-        Automatically enables the user (sets athenix.users.username.enable = true).
-        Value should be a username from athenix.users.accounts.
-      '';
-    };
-
-    host = {
-      useHostPrefix = lib.mkOption {
-        type = lib.types.bool;
-        default = true;
-        description = "Whether to prepend the host prefix to the hostname (used in inventory).";
-      };
-      filesystem = {
-        device = lib.mkOption {
-          type = lib.types.str;
-          description = "The main disk device to use for installation.";
-        };
-        useSwap = lib.mkOption {
-          type = lib.types.bool;
-          default = true;
-          description = "Whether to create and use a swap partition.";
-        };
-        swapSize = lib.mkOption {
-          type = lib.types.str;
-          description = "The size of the swap partition.";
-        };
-      };
-      buildMethods = lib.mkOption {
-        type = lib.types.listOf lib.types.str;
-        default = [ "installer-iso" ];
-        description = ''
-          List of allowed build methods for this host.
-          Supported methods:
-          - "installer-iso": Generates an auto-install ISO that installs this configuration to disk.
-          - "iso": Generates a live ISO (using nixos-generators).
-          - "ipxe": Generates iPXE netboot artifacts (kernel, initrd, script).
-          - "lxc": Generates an LXC container tarball.
-          - "proxmox": Generates a Proxmox VMA archive.
-        '';
-      };
-    };
-
-    system.gc = {
-      enable = lib.mkOption {
-        type = lib.types.bool;
-        default = true;
-        description = "Whether to enable automatic garbage collection.";
-      };
-      frequency = lib.mkOption {
-        type = lib.types.str;
-        default = "weekly";
-        description = "How often to run garbage collection (systemd timer format).";
-      };
-      retentionDays = lib.mkOption {
-        type = lib.types.int;
-        default = 30;
-        description = "Number of days to keep old generations before deletion.";
-      };
-      optimise = lib.mkOption {
-        type = lib.types.bool;
-        default = true;
-        description = "Whether to automatically optimize the Nix store.";
-      };
-    };
-  };
-
-  config = lib.mkMerge [
-    # Enable forUser if specified
-    (lib.mkIf (config.athenix.forUser != null) {
-      athenix.users.${config.athenix.forUser}.enable = true;
-    })
-
-    # Main configuration
-    {
-      # ========== Disk Partitioning (Disko) ==========
-      disko.enableConfig = lib.mkDefault true;
-
-      disko.devices = {
-        disk.main = {
-          type = "disk";
-          device = config.athenix.host.filesystem.device;
-          content = {
-            type = "gpt";
-            partitions = {
-              # EFI System Partition
-              ESP = {
-                name = "ESP";
-                label = "BOOT";
-                size = "1G";
-                type = "EF00";
-                content = {
-                  type = "filesystem";
-                  format = "vfat";
-                  mountpoint = "/boot";
-                  mountOptions = [ "umask=0077" ];
-                  extraArgs = [
-                    "-n"
-                    "BOOT"
-                  ];
-                };
-              };
-
-              # Swap Partition (size configurable per host)
-              swap = lib.mkIf config.athenix.host.filesystem.useSwap {
-                name = "swap";
-                label = "swap";
-                size = config.athenix.host.filesystem.swapSize;
-                content = {
-                  type = "swap";
-                };
-              };
-
-              # Root Partition (takes remaining space)
-              root = {
-                name = "root";
-                label = "root";
-                size = "100%";
-                content = {
-                  type = "filesystem";
-                  format = "ext4";
-                  mountpoint = "/";
-                  extraArgs = [
-                    "-L"
-                    "ROOT"
-                  ];
-                };
-              };
-            };
-          };
-        };
-      };
-
-      # Bootloader Configuration
-      boot = {
-        loader.systemd-boot.enable = true;
-        loader.efi.canTouchEfiVariables = true;
-        plymouth.enable = true;
-
-        # Enable "Silent boot"
-        consoleLogLevel = 3;
-        initrd.verbose = false;
-
-        # Hide the OS choice for bootloaders.
-        # It's still possible to open the bootloader list by pressing any key
-        # It will just not appear on screen unless a key is pressed
-        loader.timeout = lib.mkDefault 0;
-      };
-
-      # Set your time zone.
-      time.timeZone = "America/New_York";
-
-      # Select internationalisation properties.
-      i18n.defaultLocale = "en_US.UTF-8";
-
-      i18n.extraLocaleSettings = {
-        LC_ADDRESS = "en_US.UTF-8";
-        LC_IDENTIFICATION = "en_US.UTF-8";
-        LC_MEASUREMENT = "en_US.UTF-8";
-        LC_MONETARY = "en_US.UTF-8";
-        LC_NAME = "en_US.UTF-8";
-        LC_NUMERIC = "en_US.UTF-8";
-        LC_PAPER = "en_US.UTF-8";
-        LC_TELEPHONE = "en_US.UTF-8";
-        LC_TIME = "en_US.UTF-8";
-      };
-
-      systemd.sleep.extraConfig = ''
-        SuspendState=freeze
-        HibernateDelaySec=2h
-      '';
-
-      system.stateVersion = "25.11"; # Did you read the comment?
-    }
-  ];
-}

hosts/common.nix

@@ -1,47 +0,0 @@
-# ============================================================================
-# Common Modules
-# ============================================================================
-# This module contains all the common configuration shared by all host types.
-# It includes:
-# - Boot and user configuration
-# - Software configurations
-# - User management (users.nix)
-# - Home Manager integration
-# - Secret management (agenix)
-# - Disk partitioning (disko)
-# - System-wide Nix settings (experimental features, garbage collection)
-
-{ inputs }:
-{
-  config,
-  lib,
-  ...
-}:
-{
-  imports = [
-    ./boot.nix
-    ./user-config.nix
-    ../sw
-    ../users.nix
-    inputs.home-manager.nixosModules.home-manager
-    inputs.agenix.nixosModules.default
-    inputs.disko.nixosModules.disko
-  ];
-
-  system.stateVersion = "25.11";
-
-  nix.settings.experimental-features = [
-    "nix-command"
-    "flakes"
-  ];
-
-  # Automatic Garbage Collection
-  nix.gc = lib.mkIf config.athenix.system.gc.enable {
-    automatic = true;
-    dates = config.athenix.system.gc.frequency;
-    options = "--delete-older-than ${toString config.athenix.system.gc.retentionDays}d";
-  };
-
-  # Optimize storage
-  nix.optimise.automatic = config.athenix.system.gc.optimise;
-}

installer/PROXMOX_LXC.md

@@ -46,7 +46,7 @@ Add the host to `inventory.nix` with the `nix-lxc` type or ensure it has the app
 }
 ```
 
-Your host type configuration (`hosts/types/nix-lxc.nix`) should include:
+Your host type configuration (`variants/nix-lxc.nix`) should include:
 
 ```nix
 {

installer/artifacts.nix

@@ -1,6 +1,6 @@
 {
   inputs,
-  hosts,
+  fleet,
   self,
   system,
 }:
@@ -45,7 +45,7 @@ let
     nixos-generators.nixosGenerate {
       inherit system;
       specialArgs = { inherit inputs; };
-      modules = hosts.modules.${hostName} ++ [
+      modules = fleet.modules.${hostName} ++ [
         {
           disko.enableConfig = lib.mkForce false;
           services.upower.enable = lib.mkForce false;
@@ -61,7 +61,7 @@ let
     nixpkgs.lib.nixosSystem {
       inherit system;
       specialArgs = { inherit inputs; };
-      modules = hosts.modules.${hostName} ++ [
+      modules = fleet.modules.${hostName} ++ [
         "${nixpkgs}/nixos/modules/installer/netboot/netboot.nix"
         {
           disko.enableConfig = lib.mkForce false;
@@ -70,14 +70,14 @@ let
       ];
     };
 
-  hostNames = builtins.attrNames hosts.nixosConfigurations;
+  hostNames = builtins.attrNames fleet.nixosConfigurations;
 
   # Generate installer ISOs for hosts that have "installer-iso" in their buildMethods
   installerPackages = lib.listToAttrs (
     lib.concatMap (
       name:
       let
-        cfg = hosts.nixosConfigurations.${name};
+        cfg = fleet.nixosConfigurations.${name};
       in
       if lib.elem "installer-iso" cfg.config.athenix.host.buildMethods then
         [
@@ -96,7 +96,7 @@ let
     lib.concatMap (
       name:
       let
-        cfg = hosts.nixosConfigurations.${name};
+        cfg = fleet.nixosConfigurations.${name};
       in
       if lib.elem "iso" cfg.config.athenix.host.buildMethods then
         [
@@ -115,7 +115,7 @@ let
     lib.concatMap (
       name:
       let
-        cfg = hosts.nixosConfigurations.${name};
+        cfg = fleet.nixosConfigurations.${name};
       in
       if lib.elem "ipxe" cfg.config.athenix.host.buildMethods then
         [
@@ -145,7 +145,7 @@ let
     lib.concatMap (
       name:
       let
-        cfg = hosts.nixosConfigurations.${name};
+        cfg = fleet.nixosConfigurations.${name};
       in
       if lib.elem "lxc" cfg.config.athenix.host.buildMethods then
         [
@@ -164,7 +164,7 @@ let
     lib.concatMap (
       name:
       let
-        cfg = hosts.nixosConfigurations.${name};
+        cfg = fleet.nixosConfigurations.${name};
       in
       if lib.elem "proxmox" cfg.config.athenix.host.buildMethods then
         [

installer/modules.nix

@@ -6,40 +6,23 @@
 #
 # Usage in another flake:
 #   # Full host type configurations (includes hardware + software + system config)
-#   inputs.nixos-systems.nixosModules.nix-desktop
-#   inputs.nixos-systems.nixosModules.nix-laptop
+#   inputs.athenix.nixosModules.nix-desktop
+#   inputs.athenix.nixosModules.nix-laptop
 #
-#   # Software-only configurations (for custom hardware setups)
-#   # Note: These include theme.nix in home-manager.sharedModules automatically
-#   inputs.nixos-systems.nixosModules.sw-desktop
-#   inputs.nixos-systems.nixosModules.sw-headless
-#
-#   # Home Manager modules (user-level configuration)
-#   # Theme module (no parameters):
-#   home-manager.users.myuser.imports = [ inputs.nixos-systems.homeManagerModules.theme ];
-#
-#   # Neovim module (requires user parameter):
-#   home-manager.users.myuser.imports = [
-#     (inputs.nixos-systems.homeManagerModules.nvim {
-#       user = config.athenix.users.accounts.myuser;
-#     })
-#   ];
+#   # Software-only configuration (for custom hardware setups)
+#   inputs.athenix.nixosModules.sw
 
 { inputs }:
-{
-  # ========== Full Host Type Modules ==========
-  # Complete system configurations including hardware, boot, and software
-  nix-desktop = import ../hosts/types/nix-desktop.nix { inherit inputs; }; # Desktop workstations
-  nix-laptop = import ../hosts/types/nix-laptop.nix { inherit inputs; }; # Laptop systems
-  nix-surface = import ../hosts/types/nix-surface.nix { inherit inputs; }; # Surface tablets
-  nix-lxc = import ../hosts/types/nix-lxc.nix { inherit inputs; }; # Proxmox containers
-  nix-wsl = import ../hosts/types/nix-wsl.nix { inherit inputs; }; # WSL2 systems
-  nix-ephemeral = import ../hosts/types/nix-ephemeral.nix { inherit inputs; }; # Diskless/RAM-only
-
-  # ========== Software Configuration Module ==========
-  # Main software module with all athenix.sw options
+# Automatically import all variant modules from variants/ directory
+# This returns an attribute set like: { nix-desktop = ...; nix-laptop = ...; nix-lxc = ...; sw = ...; }
+(import ../variants { inherit inputs; })
+// {
+  # Software configuration module - main module with all athenix.sw options
   # Use athenix.sw.type to select profile: "desktop", "tablet-kiosk", "headless", "stateless-kiosk"
-  # Use athenix.sw.extraPackages to add additional packages
-  # Use athenix.sw.kioskUrl to set kiosk mode URL
-  sw = { inputs, ... }@args: (import ../sw/default.nix (args // { inherit inputs; }));
+  sw =
+    {
+      inputs,
+      ...
+    }@args:
+    (import ../sw/default.nix (args // { inherit inputs; }));
 }

inventory.nix

@@ -1,72 +1,78 @@
+# ============================================================================
+# Fleet Inventory
+# ============================================================================
+# Top-level keys are ALWAYS hostname prefixes. Actual hostnames are generated
+# from the devices map or count.
+#
+# Hostname generation rules:
+# - Numeric suffixes: no dash (e.g., "nix-surface1", "nix-surface2")
+# - Non-numeric suffixes: add dash (e.g., "nix-surface-alpha", "nix-surface-beta")
+# - Set athenix.host.useHostPrefix = false to use suffix as full hostname
+#
+# Format:
+#   "prefix" = {
+#     type = "nix-desktop";        # Optional: defaults to prefix name
+#     system = "x86_64-linux";     # Optional: default is x86_64-linux
+#
+#     # Option 1: Simple count (quick syntax)
+#     devices = 5;                 # Creates: prefix1, prefix2, ..., prefix5
+#
+#     # Option 2: Explicit count
+#     count = 5;                   # Creates: prefix1, prefix2, ..., prefix5
+#
+#     # Option 3: Default count (for groups with mixed devices)
+#     defaultCount = 3;            # Creates default numbered hosts
+#
+#     # Option 4: Named device configurations
+#     devices = {
+#       "1" = { ... };             # Creates: prefix1
+#       "alpha" = { ... };         # Creates: prefix-alpha
+#       "custom" = {               # Creates: custom (no prefix)
+#         athenix.host.useHostPrefix = false;
+#       };
+#     };
+#
+#     # Common config for all devices in this group
+#     overrides = {
+#       athenix.users.user1.enable = true;  # Applied to all devices in this group
+#       # ... any other config
+#     };
+#   };
+#
+# Convenience options:
+#   athenix.forUser = "username";  # Automatically enables user (sets athenix.users.username.enable = true)
+#
+# External modules (instead of config):
+#   Device values can be a config attrset with an optional 'external' field:
+#   devices."hostname" = {
+#     external = builtins.fetchGit { ... };  # Lazy: only fetched when building this host
+#     # ... additional config options
+#   };
+#   The external module will be imported and evaluated only when this specific host is built.
+#
+# Examples:
+#   "lab" = { devices = 3; };                           # Quick: lab1, lab2, lab3
+#   "lab" = { count = 3; };                             # Same as above
+#   "kiosk" = {
+#     defaultCount = 2;                                 # kiosk1, kiosk2 (default)
+#     devices."special" = {};                           # kiosk-special (custom)
+#   };
+#   "laptop" = {
+#     devices = 5;
+#     overrides.athenix.users.student.enable = true;     # All 5 laptops get this user
+#   };
+#   "wsl" = {
+#     devices."alice".athenix.forUser = "alice123";       # Sets up for user alice123
+#   };
+#   "external" = {
+#     devices."remote".external = builtins.fetchGit {     # External module via Git (lazy)
+#       url = "https://github.com/example/config";
+#       rev = "e1ccd7cc3e709afe4f50b0627e1c4bde49165014";
+#     };
+#   };  
+
 {
-  # ============================================================================
-  # Fleet Inventory
-  # ============================================================================
-  # Top-level keys are ALWAYS hostname prefixes. Actual hostnames are generated
-  # from the devices map or count.
-  #
-  # Hostname generation rules:
-  # - Numeric suffixes: no dash (e.g., "nix-surface1", "nix-surface2")
-  # - Non-numeric suffixes: add dash (e.g., "nix-surface-alpha", "nix-surface-beta")
-  # - Set athenix.host.useHostPrefix = false to use suffix as full hostname
-  #
-  # Format:
-  #   "prefix" = {
-  #     type = "nix-desktop";        # Optional: defaults to prefix name
-  #     system = "x86_64-linux";     # Optional: default is x86_64-linux
-  #
-  #     # Option 1: Simple count (quick syntax)
-  #     devices = 5;                 # Creates: prefix1, prefix2, ..., prefix5
-  #
-  #     # Option 2: Explicit count
-  #     count = 5;                   # Creates: prefix1, prefix2, ..., prefix5
-  #
-  #     # Option 3: Default count (for groups with mixed devices)
-  #     defaultCount = 3;            # Creates default numbered hosts
-  #
-  #     # Option 4: Named device configurations
-  #     devices = {
-  #       "1" = { ... };             # Creates: prefix1
-  #       "alpha" = { ... };         # Creates: prefix-alpha
-  #       "custom" = {               # Creates: custom (no prefix)
-  #         athenix.host.useHostPrefix = false;
-  #       };
-  #     };
-  #
-  #     # Common config for all devices in this group
-  #     overrides = {
-  #       athenix.users.user1.enable = true;  # Applied to all devices in this group
-  #       # ... any other config
-  #     };
-  #   };
-  #
-  # Convenience options:
-  #   athenix.forUser = "username";  # Automatically enables user (sets athenix.users.username.enable = true)
-  #
-  # External modules (instead of config):
-  #   Device values can be either a config attrset OR a fetchGit/fetchurl call
-  #   that points to an external Nix module. The module will be imported and evaluated.
-  #
-  # Examples:
-  #   "lab" = { devices = 3; };                           # Quick: lab1, lab2, lab3
-  #   "lab" = { count = 3; };                             # Same as above
-  #   "kiosk" = {
-  #     defaultCount = 2;                                 # kiosk1, kiosk2 (default)
-  #     devices."special" = {};                           # kiosk-special (custom)
-  #   };
-  #   "laptop" = {
-  #     devices = 5;
-  #     overrides.athenix.users.student.enable = true;     # All 5 laptops get this user
-  #   };
-  #   "wsl" = {
-  #     devices."alice".athenix.forUser = "alice123";       # Sets up for user alice123
-  #   };
-  #   "external" = {
-  #     devices."remote" = builtins.fetchGit {            # External module via Git
-  #       url = "https://github.com/example/config";
-  #       rev = "e1ccd7cc3e709afe4f50b0627e1c4bde49165014";
-  #     };
-  #   };  # ========== Lab Laptops ==========
+  # ========== Lab Laptops ==========
   # Creates: nix-laptop1, nix-laptop2
   # Both get hdh20267 user via overrides
   nix-laptop = {
@@ -120,7 +126,7 @@
           };
         };
       };
-      "usda-dash" = builtins.fetchGit {
+      "usda-dash".external = builtins.fetchGit {
         url = "https://git.factory.uga.edu/MODEL/usda-dash-config.git";
         rev = "dab32f5884895cead0fae28cb7d88d17951d0c12";
         submodules = true;
@@ -146,34 +152,4 @@
   # ========== Ephemeral/Netboot System ==========
   # Creates: nix-ephemeral1
   nix-ephemeral.devices = 1;
-
-  # ========== Example: External Module Configurations ==========
-  # Uncomment to use external modules from Git repositories:
-  #
-  # external-systems = {
-  #   devices = {
-  #     # Option 1: fetchGit with specific revision (recommended for reproducibility)
-  #     "prod-server" = builtins.fetchGit {
-  #       url = "https://github.com/example/server-config";
-  #       rev = "e1ccd7cc3e709afe4f50b0627e1c4bde49165014";  # Full commit hash
-  #       ref = "main";              # Optional: branch/tag name
-  #     };
-  #
-  #     # Option 2: fetchGit with latest from branch (less reproducible)
-  #     "dev-server" = builtins.fetchGit {
-  #       url = "https://github.com/example/server-config";
-  #       ref = "develop";
-  #     };
-  #
-  #     # Option 3: fetchTarball for specific release
-  #     "test-server" = builtins.fetchTarball {
-  #       url = "https://github.com/example/server-config/archive/v1.0.0.tar.gz";
-  #       sha256 = "sha256:0000000000000000000000000000000000000000000000000000";
-  #     };
-  #
-  #     # Option 4: Mix external module with local overrides
-  #     # Note: The external module's default.nix should export a NixOS module
-  #     # that accepts { inputs, ... } as parameters
-  #   };
-  # };
 }

variants/default.nix

@@ -0,0 +1,23 @@
+# ============================================================================
+# Host Types Module
+# ============================================================================
+# This module exports all available host types as an attribute set.
+# Each type is a NixOS module function that takes { inputs } and returns
+# a module configuration.
+
+{ inputs }:
+let
+  inherit (builtins) readDir attrNames;
+  lib = inputs.nixpkgs.lib;
+  inherit (lib) filterAttrs removeSuffix genAttrs;
+
+  files = readDir ./.;
+
+  # Keep only regular *.nix files except default.nix
+  nixFiles = filterAttrs (
+    name: type: type == "regular" && lib.hasSuffix ".nix" name && name != "default.nix"
+  ) files;
+
+  moduleNames = map (name: removeSuffix ".nix" name) (attrNames nixFiles);
+in
+genAttrs moduleNames (name: import ./${name}.nix { inherit inputs; })

variants/nix-desktop.nix

@@ -13,7 +13,6 @@
 }:
 {
   imports = [
-    (import ../common.nix { inherit inputs; })
     (modulesPath + "/installer/scan/not-detected.nix")
   ];
 

variants/nix-ephemeral.nix

@@ -14,7 +14,6 @@
 }:
 {
   imports = [
-    (import ../common.nix { inherit inputs; })
     (modulesPath + "/installer/scan/not-detected.nix")
   ];
 

variants/nix-laptop.nix

@@ -13,7 +13,6 @@
 }:
 {
   imports = [
-    (import ../common.nix { inherit inputs; })
     (modulesPath + "/installer/scan/not-detected.nix")
   ];
 

variants/nix-lxc.nix

@@ -13,7 +13,6 @@
 }:
 {
   imports = [
-    (import ../common.nix { inherit inputs; })
     inputs.vscode-server.nixosModules.default
     "${modulesPath}/virtualisation/proxmox-lxc.nix"
   ];

variants/nix-surface.nix

@@ -22,7 +22,6 @@ let
 in
 {
   imports = [
-    (import ../common.nix { inherit inputs; })
     (modulesPath + "/installer/scan/not-detected.nix")
     inputs.nixos-hardware.nixosModules.microsoft-surface-go
   ];

variants/nix-wsl.nix

@@ -12,7 +12,6 @@
 }:
 {
   imports = [
-    (import ../common.nix { inherit inputs; })
     inputs.nixos-wsl.nixosModules.default
     inputs.vscode-server.nixosModules.default
   ];

variants/nix-zima.nix

@@ -13,7 +13,6 @@
 }:
 {
   imports = [
-    (import ../common.nix { inherit inputs; })
     (modulesPath + "/installer/scan/not-detected.nix")
   ];