From f08f3812f40322b6098d75573413ed83f358871f Mon Sep 17 00:00:00 2001
From: Kleidi Bujari <mail@4kb.net>
Date: Sun, 1 Dec 2024 22:30:26 -0500
Subject: Cleanup xnet module and add baseline modules

With these changes, the xnet module is useable as a system builder. At
this point, it is still undecided whether all configuration will be
generalized into this module, rather than keeping mini-modules local to
the machine they will run on.
---
 modules/xnet/disk.nix | 139 ++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 139 insertions(+)
 create mode 100644 modules/xnet/disk.nix

(limited to 'modules/xnet/disk.nix')

diff --git a/modules/xnet/disk.nix b/modules/xnet/disk.nix
new file mode 100644
index 0000000..caef61d
--- /dev/null
+++ b/modules/xnet/disk.nix
@@ -0,0 +1,139 @@
+{ config, lib, modulesPath, ... }:
+let
+  cfg = config.xnet.disk;
+  commonOpts = {
+    acltype = "posixacl";
+    atime = "off";
+    compression = "on";
+    normalization = "formD";
+    relatime = "off";
+    xattr = "sa";
+    "com.sun:auto-snapshot" = "false";
+  };
+
+  inherit (lib) mkOption mkDefault mkIf types;
+in
+{
+  imports = [
+    (modulesPath + "/installer/scan/not-detected.nix")
+  ];
+
+  options.xnet.disk = {
+    enable = mkOption {
+      type = types.bool;
+      default = false;
+      description = "Apply xnet-standard ZFS disk layout.";
+    };
+
+    device = mkOption {
+      type = types.str;
+      description = "Device used for zroot ZFS pool.";
+    };
+  };
+
+  config = mkIf cfg.enable {
+    networking.hostId = builtins.substring 0 8
+      (builtins.hashString "md5" config.networking.hostName);
+
+    services.zfs = {
+      autoScrub.enable = true;
+      trim.enable = true;
+    };
+
+    # With root running in memory, swap should be required unless
+    # otherwise specified
+    zramSwap.enable = mkDefault true;
+
+    boot = {
+      kernelParams = [ "nohibernate" "elevator=none" ];
+      supportedFilesystems = [ "vfat" "zfs" ];
+      zfs.devNodes = "/dev/disk/by-partuuid";
+      loader = {
+        systemd-boot.enable = true;
+        efi.canTouchEfiVariables = true;
+      };
+      initrd = {
+        systemd.enable = true;
+        availableKernelModules = [
+          "xhci_pci"
+          "ahci"
+          "nvme"
+          "usb_storage"
+          "sd_mod"
+          "sdhci_pci"
+        ];
+      };
+      tmp.cleanOnBoot = mkDefault true;
+    };
+
+    disko.devices.disk.main = {
+      type = "disk";
+      device = cfg.device;
+      content = {
+        type = "gpt";
+        partitions.ESP = {
+          size = "1G";
+          type = "EF00";
+          content = {
+            type = "filesystem";
+            format = "vfat";
+            mountpoint = "/boot";
+          };
+        };
+        partitions.ZFS = {
+          size = "100%";
+          content = {
+            type = "zfs";
+            pool = "zroot";
+          };
+        };
+      };
+    };
+
+    disko.devices = {
+      nodev."/" = {
+        fsType = "tmpfs";
+        mountOptions = [ "defaults" "size=2G" "mode=755" ];
+      };
+
+      zpool.zroot = {
+        type = "zpool";
+        options = {
+          ashift = "12";
+          autotrim = "on";
+        };
+
+        datasets = {
+          "local" = {
+            type = "zfs_fs";
+            options = commonOpts // {
+              mountpoint = "none";
+            };
+          };
+
+          "local/nix" = {
+            type = "zfs_fs";
+            mountpoint = "/nix";
+            options.mountpoint = "legacy";
+          };
+
+          "local/reserved" = {
+            type = "zfs_fs";
+            options = {
+              refreservation = "10G";
+              mountpoint = "none";
+            };
+          };
+
+          "persist" = {
+            type = "zfs_fs";
+            mountpoint = "/persist";
+            options = commonOpts // {
+              mountpoint = "legacy";
+            };
+          };
+        };
+      };
+    };
+  };
+}
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