Group shared system settings

system/shared/boot/generic.nix

@@ -0,0 +1,58 @@
+{ config, lib, ... }: let
+  inherit (lib) mkDefault optionals;
+
+  cfg = config.myOptions.system.boot;
+in {
+  boot = {
+    # kernel console loglevel
+    consoleLogLevel = 3;
+
+    # The NixOS default is to use an lts kernel, which can be quite old.
+    # My configuration defaults to the latest kernel instead
+    kernelPackages = cfg.kernel;
+
+    loader = {
+      # if set to 0, space needs to be held to get the boot menu to appear
+      timeout = 2;
+
+      # whether to copy the necessary boot files into /boot
+      # so that /nix/store is not needed by the boot loader.
+      generationsDir.copyKernels = true;
+
+      # allow installation to modify EFI variables
+      efi.canTouchEfiVariables = true;
+    };
+
+    tmp = {
+      # /tmp on tmpfs, lets it live on your ram
+      # it defaults to false, which means you will use disk space instead of ram 
+      # enable tmpfs tmp on anything where you have ram to spare
+      useTmpfs = cfg.tmpOnTmpfs;
+
+      # if not using tmpfs, which is naturally purged on reboot, we must clean
+      # /tmp ourselves. /tmp should be volatile storage!
+      cleanOnBoot = mkDefault (!cfg.tmpOnTmpfs);
+
+      # The size of the tmpfs, in percentage form
+      # this defaults to 50% of your ram, which is a good default
+      # but should be tweaked based on your systems capabilities
+      tmpfsSize = mkDefault "50%";
+    };
+
+    kernelParams = (optionals cfg.silentBoot [
+      # tell the kernel to not be verbose
+      "quiet"
+
+      "loglevel=3" # 1: system is unusable | 3: error condition | 7: very verbose
+
+      # udev log message level
+      # rd prefix means systemd-udev will be used instead of initrd
+      "udev.log_level=3"
+      "rd.udev.log_level=3"
+
+      # disable systemd status messages
+      "systemd.show_status=auto"
+      "rd.systemd.show_status=auto"
+    ]);
+  };
+}