Add impermanence setup to SIIT-DC

hosts/siit-dc/configuration.nix

@@ -1,9 +1,13 @@
 { ... }:
 {
+  networking.hostId = "f1636fe0";
   imports = [
     ../../shared/base.nix
+
+    ../../shared/hardware/impermanence.nix
     ../../shared/hardware/vm.nix
-    ../../shared/disko/hetzner-ext4.nix
+
+    ../../shared/disko/hetzner-zfs-impermanence.nix
 
     ../../servers/siit-dc.nix
   ];

shared/disko/hetzner-zfs-impermanence.nix

@@ -0,0 +1,76 @@
+{
+  disko.devices = {
+    disk = {
+      main = {
+        device = "/dev/sda";
+        type = "disk";
+        content = {
+          type = "gpt";
+          partitions = {
+            boot = {
+              size = "1M";
+              type = "EF02";
+              priority = 1;
+            };
+            ESP = {
+              size = "512M";
+              type = "EF00";
+              content = {
+                type = "filesystem";
+                format = "vfat";
+                mountpoint = "/boot";
+                mountOptions = [ "umask=0077" ];
+              };
+            };
+            zfs = {
+              size = "100%";
+              content = {
+                type = "zfs";
+                pool = "zroot";
+              };
+            };
+          };
+        };
+      };
+    };
+    zpool = {
+      zroot = {
+        type = "zpool";
+        rootFsOptions = {
+          canmount = "off";
+          compression = "zstd";
+        };
+        datasets = {
+          root = {
+            type = "zfs_fs";
+            mountpoint = "/";
+            options.mountpoint = "legacy";
+            postCreateHook = "zfs snapshot zroot/root@blank";
+          };
+          nix = {
+            type = "zfs_fs";
+            mountpoint = "/nix";
+            options.mountpoint = "legacy";
+          };
+          persist = {
+            type = "zfs_fs";
+            options = {
+              mountpoint = "legacy";
+              "com.sun:auto-snapshot" = "true";
+            };
+            mountpoint = "/persist";
+          };
+          home = {
+            type = "zfs_fs";
+            options = {
+              mountpoint = "legacy";
+              "com.sun:auto-snapshot" = "true";
+            };
+            mountpoint = "/home";
+            postCreateHook = "zfs snapshot zroot/home@blank";
+          };
+        };
+      };
+    };
+  };
+}

shared/hardware/impermanence.nix

@@ -0,0 +1,15 @@
+{ lib, ... }:
+{
+  services.zfs = {
+    autoScrub.enable = true;
+    autoSnapshot = {
+      enable = true;
+      flags = "-k -p --utc";
+    };
+  };
+
+  boot.initrd.postResumeCommands = lib.mkAfter ''
+    zfs rollback -r zroot/root@blank
+    zfs rollback -r zroot/home@blank
+  '';
+}