feat(vps): add impermanence

hosts/vps/default.nix

@@ -1,121 +1,94 @@
 {
   modulesPath,
   inputs,
-  outputs,
-  pkgs,
   username,
-  email,
+  lib,
   ...
 }: {
   imports = [
     (modulesPath + "/installer/scan/not-detected.nix")
     (modulesPath + "/profiles/qemu-guest.nix")
     inputs.disko.nixosModules.default
-    inputs.home-manager.nixosModules.home-manager
     (import ./disko.nix {device = "/dev/sda";})
+
+    ../common
   ];
 
   nixpkgs = {
     hostPlatform = "x86_64-linux";
+  };
 
-    overlays = [
-      outputs.overlays.additions
-      outputs.overlays.modifications
-      outputs.overlays.unstable-packages
-      outputs.overlays.nur
-    ];
+  boot = {
+    initrd.systemd = {
+      enable = lib.mkForce true;
 
-    config = {
-      allowUnfree = true;
-      joypixels.acceptLicense = true;
+      services.wipe-my-fs = {
+        wantedBy = ["initrd.target"];
+        after = ["initrd-root-device.target"];
+        before = ["sysroot.mount"];
+        unitConfig.DefaultDependencies = "no";
+        serviceConfig.Type = "oneshot";
+        script = ''
+          mkdir /btrfs_tmp
+          mount /dev/disk/by-partlabel/disk-primary-root /btrfs_tmp
+
+          if [[ -e /btrfs_tmp/root ]]; then
+              mkdir -p /btrfs_tmp/old_roots
+              timestamp=$(date --date="@$(stat -c %Y /btrfs_tmp/root)" "+%Y-%m-%-d_%H:%M:%S")
+              mv /btrfs_tmp/root "/btrfs_tmp/old_roots/$timestamp"
+          fi
+
+          delete_subvolume_recursively() {
+              IFS=$'\n'
+              for i in $(btrfs subvolume list -o "$1" | cut -f 9- -d ' '); do
+                  delete_subvolume_recursively "/btrfs_tmp/$i"
+              done
+              btrfs subvolume delete "$1"
+          }
+
+          for i in $(find /btrfs_tmp/old_roots/ -maxdepth 1 -mtime +30); do
+              delete_subvolume_recursively "$i"
+          done
+
+          btrfs subvolume create /btrfs_tmp/root
+          umount /btrfs_tmp
+        '';
+      };
     };
-  };
 
-  nix = {
-    package = pkgs.lix;
-    settings = {
-      experimental-features = "nix-command flakes";
-      auto-optimise-store = true;
-      trusted-users = ["${username}"];
-      warn-dirty = false;
-      substituters = [
-        "https://cache.nixos.org?priority=10"
-        "https://anyrun.cachix.org"
-        "https://fufexan.cachix.org"
-        "https://helix.cachix.org"
-        "https://hyprland.cachix.org"
-        "https://nix-community.cachix.org"
-        "https://nix-gaming.cachix.org"
-        "https://yazi.cachix.org"
-      ];
-      trusted-public-keys = [
-        "cache.nixos.org-1:6NCHdD59X431o0gWypbMrAURkbJ16ZPMQFGspcDShjY="
-        "anyrun.cachix.org-1:pqBobmOjI7nKlsUMV25u9QHa9btJK65/C8vnO3p346s="
-        "fufexan.cachix.org-1:LwCDjCJNJQf5XD2BV+yamQIMZfcKWR9ISIFy5curUsY="
-        "helix.cachix.org-1:ejp9KQpR1FBI2onstMQ34yogDm4OgU2ru6lIwPvuCVs="
-        "hyprland.cachix.org-1:a7pgxzMz7+chwVL3/pzj6jIBMioiJM7ypFP8PwtkuGc="
-        "nix-community.cachix.org-1:mB9FSh9qf2dCimDSUo8Zy7bkq5CX+/rkCWyvRCYg3Fs="
-        "nix-gaming.cachix.org-1:nbjlureqMbRAxR1gJ/f3hxemL9svXaZF/Ees8vCUUs4="
-        "yazi.cachix.org-1:Dcdz63NZKfvUCbDGngQDAZq6kOroIrFoyO064uvLh8k="
-      ];
-    };
-  };
-
-  boot.loader.grub = {
-    efiSupport = true;
-    efiInstallAsRemovable = true;
-  };
-
-  networking.hostName = "vps";
-
-  time.timeZone = "Asia/Kolkata";
-  i18n = {
-    defaultLocale = "en_US.UTF-8";
-    extraLocaleSettings = {
-      LC_ADDRESS = "en_IN";
-      LC_IDENTIFICATION = "en_IN";
-      LC_MEASUREMENT = "en_IN";
-      LC_MONETARY = "en_IN";
-      LC_NAME = "en_IN";
-      LC_NUMERIC = "en_IN";
-      LC_PAPER = "en_IN";
-      LC_TELEPHONE = "en_IN";
-      LC_TIME = "en_IN";
-    };
-  };
-
-  programs = {
-    zsh.enable = true;
-    nh = {
-      enable = true;
-      clean.enable = true;
-      clean.extraArgs = "--keep-since 5d --keep 5";
-      flake = "/home/${username}/Projects/nixos-config";
-    };
-  };
-
-  services = {
-    openssh = {
-      enable = true;
-      settings = {
-        PasswordAuthentication = false;
+    loader = {
+      grub = {
+        efiSupport = true;
+        efiInstallAsRemovable = true;
       };
     };
   };
 
+  networking.hostName = "vps";
+
   users = {
-    mutableUsers = false;
-    defaultUserShell = pkgs.zsh;
     users.${username} = {
       password = "${username}";
-      isNormalUser = true;
-      extraGroups = ["networkmanager" "wheel" "storage"];
-      openssh.authorizedKeys.keys = [
-        ''ssh-ed25519 AAAAC3NzaC1lZDI1NTE5AAAAIL+OzPUe2ECPC929DqpkM39tl/vdNAXfsRnmrGfR+X3D ${email}''
-      ];
+      hashedPasswordFile = lib.mkForce null;
     };
   };
 
+  programs.fuse.userAllowOther = true;
+  fileSystems."/persist".neededForBoot = true;
+  environment.persistence."/persist" = {
+    hideMounts = true;
+    directories = [
+      "/var/log"
+      "/var/lib/nixos"
+    ];
+    files = [
+      "/etc/ssh/ssh_host_ed25519_key"
+      "/etc/ssh/ssh_host_ed25519_key.pub"
+      "/etc/ssh/ssh_host_rsa_key"
+      "/etc/ssh/ssh_host_rsa_key.pub"
+    ];
+  };
+
   home-manager.users.${username} = {
     imports = [
       ./home.nix

hosts/vps/disko.nix

@@ -1,50 +1,49 @@
 {device ? throw "Set this to the disk device, e.g. /dev/nvme0n1", ...}: {
-  disko.devices = {
-    disk.primary = {
-      inherit device;
-      type = "disk";
-      content = {
-        type = "gpt";
-        partitions = {
-          boot = {
-            name = "boot";
-            size = "1M";
-            type = "EF02";
-          };
-          esp = {
-            name = "ESP";
-            size = "500M";
-            type = "EF00";
-            content = {
-              type = "filesystem";
-              format = "vfat";
-              mountpoint = "/boot";
-            };
-          };
-          root = {
-            name = "root";
-            size = "100%";
-            content = {
-              type = "lvm_pv";
-              vg = "pool";
-            };
+  disko.devices.disk.primary = {
+    inherit device;
+    type = "disk";
+    content = {
+      type = "gpt"; # GPT partitioning scheme
+      partitions = {
+        boot = {
+          name = "boot";
+          size = "1M";
+          type = "EF02";
+        };
+        # EFI Partition
+        ESP = {
+          size = "512M";
+          type = "EF00";
+          content = {
+            type = "filesystem";
+            format = "vfat";
+            mountpoint = "/boot";
+            mountOptions = ["defaults" "umask=0077"];
           };
         };
-      };
-    };
-    lvm_vg = {
-      pool = {
-        type = "lvm_vg";
-        lvs = {
-          root = {
-            size = "100%FREE";
-            content = {
-              type = "filesystem";
-              format = "ext4";
-              mountpoint = "/";
-              mountOptions = [
-                "defaults"
-              ];
+        # Btrfs Root Partition
+        root = {
+          size = "100%"; # Use remaining space
+          type = "8300"; # Linux filesystem type
+          content = {
+            type = "btrfs";
+            subvolumes = {
+              "/root" = {
+                mountOptions = ["compress=zstd"]; # Compression for better performance
+                mountpoint = "/"; # Root subvolume
+              };
+              "/persist" = {
+                mountOptions = ["compress=zstd"]; # Compression for persistent data
+                mountpoint = "/persist"; # Persistent subvolume
+              };
+              "/nix" = {
+                mountOptions = [
+                  "compress=zstd"
+                  "noatime"
+                  "noacl"
+                ]; # Optimize for Nix store
+                mountpoint = "/nix"; # Nix subvolume
+              };
             };
           };
         };

hosts/vps/home.nix

@@ -1,7 +1,15 @@
-{...}: {
-  imports = [
-    ../common/home.nix
-  ];
+{username, ...}: {
+  home.persistence."/persist/home/${username}" = {
+    directories = [
+      "Projects"
+      ".ssh"
+    ];
+    files = [
+      ".zsh_history"
+      ".zcompdump"
+    ];
+    allowOther = true;
+  };
 
   home.stateVersion = "24.11";
 }