made disko/impermanence config into a module

2024-12-10 23:43:53 -06:00 · 2024-12-10 23:43:53 -06:00 · 30ad3c91b9
commit 30ad3c91b9
parent c28731a1a7
10 changed files with 571 additions and 466 deletions
--- a/modules/nixos-modules/impermanence.nix
+++ b/modules/nixos-modules/impermanence.nix
@ -0,0 +1,110 @@
+{
+  config,
+  lib,
+  ...
+}: {
+  options.host.impermanence.enable = lib.mkEnableOption "are we going to use impermanence on this device";
+
+  # TODO: validate that config.host.storage.enable is enabled
+  config = lib.mkMerge [
+    {
+      assertions = [
+        {
+          assertion = !(config.host.impermanence.enable && !config.host.storage.enable);
+          message = ''
+            Disko storage must be enabled to use impermanence.
+          '';
+        }
+      ];
+    }
+    (
+      lib.mkIf config.host.impermanence.enable {
+        boot.initrd.postResumeCommands = lib.mkAfter ''
+                    zfs rollback -r rpool/local/system/root@blank
+          1        '';
+
+        fileSystems = {
+          "/".neededForBoot = true;
+          "/persist/system/root".neededForBoot = true;
+        };
+
+        host.storage.pool.extraDatasets = {
+          # local datasets are for data that should be considered ephemeral
+          "local" = {
+            type = "zfs_fs";
+            options.canmount = "off";
+          };
+          # nix directory needs to be available pre persist and doesn't need to be snapshotted or backed up
+          "local/system/nix" = {
+            type = "zfs_fs";
+            mountpoint = "/nix";
+            options = {
+              atime = "off";
+              relatime = "off";
+              canmount = "on";
+            };
+          };
+          # dataset for root that gets rolled back on every boot
+          "local/system/root" = {
+            type = "zfs_fs";
+            mountpoint = "/";
+            options = {
+              canmount = "on";
+            };
+            postCreateHook = ''
+              zfs snapshot rpool/local/system/root@blank
+            '';
+          };
+
+          # persist datasets are datasets that contain information that we would like to keep around
+          "persist" = {
+            type = "zfs_fs";
+            options.canmount = "off";
+          };
+          # this is where root data actually lives
+          "persist/system/root" = {
+            type = "zfs_fs";
+            mountpoint = "/persist/system/root";
+            options = {
+              "com.sun:auto-snapshot" = "true";
+            };
+          };
+          "persist/system/var/log" = {
+            type = "zfs_fs";
+            mountpoint = "/persist/system/var/log";
+          };
+        };
+
+        environment.persistence."/persist/system/root" = {
+          enable = true;
+          hideMounts = true;
+          directories = [
+            "/etc/ssh"
+
+            "/var/log"
+            "/var/lib/nixos"
+            "/var/lib/systemd/coredump"
+
+            # config.apps.pihole.directory.root
+
+            # config.apps.jellyfin.mediaDirectory
+            # config.services.jellyfin.configDir
+            # config.services.jellyfin.cacheDir
+            # config.services.jellyfin.dataDir
+
+            # "/var/hass" # config.users.users.hass.home
+            # "/var/postgresql" # config.users.users.postgresql.home
+            # "/var/forgejo" # config.users.users.forgejo.home
+            # "/var/nextcloud" # config.users.users.nextcloud.home
+            # "/var/headscale" # config.users.users.headscale.home
+          ];
+          files = [
+            "/etc/machine-id"
+          ];
+        };
+
+        security.sudo.extraConfig = "Defaults lecture=never";
+      }
+    )
+  ];
+}