feat(nixos): add disko module for declarative partitioning

flake.lock

@@ -35,6 +35,26 @@
         "type": "github"
       }
     },
+    "disko": {
+      "inputs": {
+        "nixpkgs": [
+          "nixpkgs"
+        ]
+      },
+      "locked": {
+        "lastModified": 1751854533,
+        "narHash": "sha256-U/OQFplExOR1jazZY4KkaQkJqOl59xlh21HP9mI79Vc=",
+        "owner": "nix-community",
+        "repo": "disko",
+        "rev": "16b74a1e304197248a1bc663280f2548dbfcae3c",
+        "type": "github"
+      },
+      "original": {
+        "owner": "nix-community",
+        "repo": "disko",
+        "type": "github"
+      }
+    },
     "files": {
       "locked": {
         "lastModified": 1750263550,
@@ -171,6 +191,7 @@
       "inputs": {
         "dedupe_flake-compat": "dedupe_flake-compat",
         "dedupe_gitignore": "dedupe_gitignore",
+        "disko": "disko",
         "files": "files",
         "flake-parts": "flake-parts",
         "git-hooks": "git-hooks",

flake.nix

@@ -14,6 +14,11 @@
       url = "github:nix-community/home-manager";
       inputs.nixpkgs.follows = "nixpkgs";
     };
+    # disko provides declarative drive partitioning
+    disko = {
+      url = "github:nix-community/disko";
+      inputs.nixpkgs.follows = "nixpkgs";
+    };
     # import-tree imports all nix files in a given directory.
     import-tree.url = "github:vic/import-tree";
     # files lets us write text files and automatically add checks for them

nix/manifest.nix

@@ -2,10 +2,6 @@ let
   testCfg =
     { hostName, ... }:
     {
-      fileSystems."/" = {
-        device = "/dev/sda1";
-        fsType = "ext4";
-      };
       boot.loader.systemd-boot.enable = true;
       networking = { inherit hostName; };
     };

nix/modules/machine/root.nix

@@ -0,0 +1,75 @@
+{ config, inputs, ... }:
+{
+  flake.modules.nixos.default =
+    { hostName, ... }:
+    {
+      imports = [ inputs.disko.nixosModules.disko ];
+      boot.initrd.kernelModules = [ "dm-snapshot" ];
+      # BTRFS - may add more later on
+      disko.devices.disk.main = {
+        device = config.flake.manifest.hosts.nixos.${hostName}.machine.root.drive;
+        type = "disk";
+        content.type = "gpt";
+        content.partitions = {
+          boot = {
+            name = "boot";
+            size = "1M";
+            type = "EF02";
+          };
+          esp = {
+            name = "ESP";
+            size = "500M";
+            type = "EF00";
+            content = {
+              type = "filesystem";
+              format = "vfat";
+              mountpoint = "/boot";
+            };
+          };
+          swap = {
+            size = "4G";
+            content = {
+              type = "swap";
+              resumeDevice = true;
+            };
+          };
+          root = {
+            name = "root";
+            size = "100%";
+            content = {
+              type = "lvm_pv";
+              vg = "root_vg";
+            };
+          };
+        };
+      };
+
+      disko.devices.lvm_vg.root_vg = {
+        type = "lvm_vg";
+        lvs.root = {
+          size = "100%FREE";
+          content = {
+            type = "btrfs";
+            extraArgs = [ "-f" ];
+            subvolumes = {
+              "/root".mountpoint = "/";
+              "/persist" = {
+                mountpoint = "/persist";
+                mountOptions = [
+                  "subvol=persist"
+                  "noatime"
+                ];
+              };
+              "/nix" = {
+                mountpoint = "/nix";
+                mountOptions = [
+                  "subvol=nix"
+                  "noatime"
+                ];
+              };
+            };
+          };
+        };
+      };
+    };
+}