bootloader choice

modules/core/config.nix

@@ -89,5 +89,25 @@ in
         settings.PermitRootLogin = allowRootSSH;
       };
     };
+
+    boot.loader =
+      if cfg.bootloader == "grub" then
+        {
+          grub = {
+            enable = cfg.grub.enable;
+            device = cfg.grub.device;
+          };
+
+          systemd-boot.enable = false;
+        }
+      else
+        {
+          systemd-boot = {
+            enable = cfg.systemd.enable;
+            efiSupport = cfg.systemd.efiSupport;
+          };
+
+          grub.enable = false;
+        };
   };
 }

modules/core/options.nix

@@ -11,6 +11,54 @@
       description = "The kernel of the machine";
     };
 
+    bootloader = {
+      type = lib.mkOption {
+        type = lib.types.enum [
+          "grub"
+          "systemd"
+        ];
+        default = "grub";
+        description = "Which bootloader to use (grub or systemd-boot)";
+      };
+
+      grub = lib.mkOption {
+        type = lib.types.submodule {
+          options = {
+            enable = lib.mkOption {
+              type = lib.types.bool;
+              default = false;
+            };
+
+            device = lib.mkOption {
+              type = lib.types.str;
+              default = "nodev";
+              description = "Device to install GRUB on";
+            };
+          };
+        };
+        default = { };
+        description = "GRUB configuration block";
+      };
+
+      systemd = lib.mkOption {
+        type = lib.types.submodule {
+          options = {
+            enable = lib.mkOption {
+              type = lib.types.bool;
+              default = false;
+            };
+
+            efiSupport = lib.mkOption {
+              type = lib.types.bool;
+              default = true;
+            };
+          };
+        };
+        default = { };
+        description = "systemd-boot configuration block";
+      };
+    };
+
     user = {
       name = lib.mkOption {
         type = lib.types.str;