diff --git a/hosts/andromache/meta.nix b/hosts/andromache/meta.nix
index 171cb53..63285bf 100644
--- a/hosts/andromache/meta.nix
+++ b/hosts/andromache/meta.nix
@@ -1,8 +1,8 @@
 {
   system = "x86_64-linux";
-  role = "desktop";
   tags = [ "personal" ];
   host = {
+    role = "desktop";
     username = "h";
     highRam = true;
     admin = true;
diff --git a/hosts/astyanax/meta.nix b/hosts/astyanax/meta.nix
index 3b7f792..06db80e 100644
--- a/hosts/astyanax/meta.nix
+++ b/hosts/astyanax/meta.nix
@@ -1,8 +1,8 @@
 {
   system = "x86_64-linux";
-  role = "laptop";
   tags = [ "personal" ];
   host = {
+    role = "laptop";
     username = "h";
     highRam = true;
     admin = true;
diff --git a/hosts/eetion-02/meta.nix b/hosts/eetion-02/meta.nix
index 6b1e816..7d1c360 100644
--- a/hosts/eetion-02/meta.nix
+++ b/hosts/eetion-02/meta.nix
@@ -1,8 +1,8 @@
 {
   system = "aarch64-linux";
-  role = "embedded";
   tags = [ "lab" ];
   host = {
+    role = "embedded";
     username = "h";
   };
 }
diff --git a/hosts/eetion/meta.nix b/hosts/eetion/meta.nix
index 6b1e816..7d1c360 100644
--- a/hosts/eetion/meta.nix
+++ b/hosts/eetion/meta.nix
@@ -1,8 +1,8 @@
 {
   system = "aarch64-linux";
-  role = "embedded";
   tags = [ "lab" ];
   host = {
+    role = "embedded";
     username = "h";
   };
 }
diff --git a/hosts/hecuba/meta.nix b/hosts/hecuba/meta.nix
index a84611f..25c041d 100644
--- a/hosts/hecuba/meta.nix
+++ b/hosts/hecuba/meta.nix
@@ -1,9 +1,9 @@
 {
   system = "x86_64-linux";
-  role = "server";
   tags = [ "lab" ];
   deploy.autoRollback = true;
   host = {
+    role = "server";
     username = "h";
   };
 }
diff --git a/hosts/vm/meta.nix b/hosts/vm/meta.nix
index 61e7dd2..f1e9d2c 100644
--- a/hosts/vm/meta.nix
+++ b/hosts/vm/meta.nix
@@ -1,8 +1,8 @@
 {
   system = "x86_64-linux";
-  role = "vm";
   tags = [ "lab" ];
   host = {
+    role = "vm";
     username = "h";
   };
 }
diff --git a/modules/common/default.nix b/modules/common/default.nix
index 006c103..3d24c11 100644
--- a/modules/common/default.nix
+++ b/modules/common/default.nix
@@ -1,92 +1,23 @@
-{
-  inputs,
-  outputs,
-  dotsPath,
-  myUtils,
-  config,
-  ...
-}:
+{ lib, ... }:
 
-let
-  inherit (inputs.nixpkgs) lib;
-  homeDir = ../../home/hosts + "/${config.host.name}";
-in
 {
   imports = [
-    inputs.home-manager.nixosModules.default
+    ./embedded.nix
+    ./home-manager.nix
     ./host.nix
+    ./nix.nix
+    ./nixpkgs.nix
+    ./upgrades.nix
   ];
 
-  options.nixpkgs.allowedUnfree = lib.mkOption {
-    type = lib.types.listOf lib.types.str;
-    default = [ ];
-  };
-
   config = {
     system.stateVersion = lib.mkDefault "25.05";
     boot.zfs.forceImportRoot = lib.mkDefault false;
 
-    nix = {
-      nixPath = [ "nixpkgs=${inputs.nixpkgs}" ]; # https://github.com/nix-community/nixd/blob/main/nixd/docs/configuration.md
-      optimise = {
-        automatic = true;
-        dates = [ "05:00" ];
-      };
-      gc = {
-        automatic = true;
-        dates = "weekly";
-        options = lib.mkDefault "--delete-older-than 30d";
-      };
-      settings.experimental-features = [
-        "nix-command"
-        "flakes"
-      ];
-      settings.trusted-public-keys = [
-        "nix-signing-key:M6ouQRFl/bZ5QQrceQUyar6P7o8qg4wwVkxD1SSLL2k="
-      ];
-    };
-
-    system.autoUpgrade = {
-      enable = true;
-      flags = [
-        "--recreate-lock-file"
-        "--commit-lock-file"
-        "--print-build-logs"
-        "--refresh"
-      ];
-      dates = "05:00";
-      randomizedDelaySec = "45min";
-      allowReboot = false;
-    };
-
-    nixpkgs.config.allowUnfreePredicate =
-      pkg: builtins.elem (lib.getName pkg) config.nixpkgs.allowedUnfree;
-
     environment.defaultPackages = lib.mkForce [ ];
     environment.pathsToLink = [
       "/share/applications"
       "/share/xdg-desktop-portal"
     ];
-
-    home-manager = {
-      useGlobalPkgs = true;
-      useUserPackages = true;
-      extraSpecialArgs = {
-        inherit
-          inputs
-          outputs
-          dotsPath
-          myUtils
-          ;
-      };
-      sharedModules = [
-        {
-          host.username = lib.mkDefault config.host.username;
-        }
-      ];
-      users = lib.optionalAttrs (builtins.pathExists homeDir) {
-        ${config.host.username} = import homeDir;
-      };
-    };
   };
 }
diff --git a/modules/common/embedded.nix b/modules/common/embedded.nix
new file mode 100644
index 0000000..3f66f7a
--- /dev/null
+++ b/modules/common/embedded.nix
@@ -0,0 +1,15 @@
+{ lib, config, ... }:
+
+{
+  config = lib.mkIf (config.host.role == "embedded") {
+    system.autoUpgrade.enable = false;
+    nix.settings.max-jobs = 0;
+
+    zramSwap = {
+      enable = true;
+      memoryPercent = 100;
+    };
+
+    services.journald.settings.Journal.SystemMaxUse = "100M";
+  };
+}
diff --git a/modules/common/home-manager.nix b/modules/common/home-manager.nix
new file mode 100644
index 0000000..0b09f51
--- /dev/null
+++ b/modules/common/home-manager.nix
@@ -0,0 +1,37 @@
+{
+  inputs,
+  outputs,
+  dotsPath,
+  myUtils,
+  config,
+  lib,
+  ...
+}:
+
+let
+  homeDir = ../../home/hosts + "/${config.host.name}";
+in
+{
+  imports = [ inputs.home-manager.nixosModules.default ];
+
+  config.home-manager = {
+    useGlobalPkgs = true;
+    useUserPackages = true;
+    extraSpecialArgs = {
+      inherit
+        inputs
+        outputs
+        dotsPath
+        myUtils
+        ;
+    };
+    sharedModules = [
+      {
+        host.username = lib.mkDefault config.host.username;
+      }
+    ];
+    users = lib.optionalAttrs (builtins.pathExists homeDir) {
+      ${config.host.username} = import homeDir;
+    };
+  };
+}
diff --git a/modules/common/host.nix b/modules/common/host.nix
index dbf7101..027c262 100644
--- a/modules/common/host.nix
+++ b/modules/common/host.nix
@@ -10,6 +10,16 @@
       type = lib.types.str;
     };
 
+    role = lib.mkOption {
+      type = lib.types.enum [
+        "desktop"
+        "embedded"
+        "laptop"
+        "server"
+        "vm"
+      ];
+    };
+
     tags = lib.mkOption {
       type = lib.types.listOf lib.types.str;
       default = [ ];
diff --git a/modules/common/nix.nix b/modules/common/nix.nix
new file mode 100644
index 0000000..18c90d5
--- /dev/null
+++ b/modules/common/nix.nix
@@ -0,0 +1,23 @@
+{ inputs, lib, ... }:
+
+{
+  config.nix = {
+    nixPath = [ "nixpkgs=${inputs.nixpkgs}" ]; # https://github.com/nix-community/nixd/blob/main/nixd/docs/configuration.md
+    optimise = {
+      automatic = true;
+      dates = [ "05:00" ];
+    };
+    gc = {
+      automatic = true;
+      dates = "weekly";
+      options = lib.mkDefault "--delete-older-than 30d";
+    };
+    settings.experimental-features = [
+      "nix-command"
+      "flakes"
+    ];
+    settings.trusted-public-keys = [
+      "nix-signing-key:M6ouQRFl/bZ5QQrceQUyar6P7o8qg4wwVkxD1SSLL2k="
+    ];
+  };
+}
diff --git a/modules/common/nixpkgs.nix b/modules/common/nixpkgs.nix
new file mode 100644
index 0000000..f8991d7
--- /dev/null
+++ b/modules/common/nixpkgs.nix
@@ -0,0 +1,11 @@
+{ lib, config, ... }:
+
+{
+  options.nixpkgs.allowedUnfree = lib.mkOption {
+    type = lib.types.listOf lib.types.str;
+    default = [ ];
+  };
+
+  config.nixpkgs.config.allowUnfreePredicate =
+    pkg: builtins.elem (lib.getName pkg) config.nixpkgs.allowedUnfree;
+}
diff --git a/modules/common/upgrades.nix b/modules/common/upgrades.nix
new file mode 100644
index 0000000..ff02a45
--- /dev/null
+++ b/modules/common/upgrades.nix
@@ -0,0 +1,16 @@
+{ lib, ... }:
+
+{
+  config.system.autoUpgrade = {
+    enable = lib.mkDefault true;
+    flags = [
+      "--recreate-lock-file"
+      "--commit-lock-file"
+      "--print-build-logs"
+      "--refresh"
+    ];
+    dates = "05:00";
+    randomizedDelaySec = "45min";
+    allowReboot = false;
+  };
+}