From 7e05e5ddc0101555d41885a2d65f3898b35cc1c5 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Vili=20Sinerv=C3=A4?= <vili.m.sinerva@gmail.com>
Date: Sun, 29 Jun 2025 15:25:07 +0300
Subject: [PATCH] Switch to impermanence

---
 flake.lock                       | 32 ++++++++++++-------------
 flake.nix                        |  6 ++---
 hosts/siit-dc/configuration.nix  |  2 +-
 shared/base.nix                  | 41 ++++++++++++--------------------
 shared/hardware/impermanence.nix |  2 ++
 5 files changed, 37 insertions(+), 46 deletions(-)

diff --git a/flake.lock b/flake.lock
index 3763152..91f9ea8 100644
--- a/flake.lock
+++ b/flake.lock
@@ -59,6 +59,21 @@
         "type": "github"
       }
     },
+    "impermanence": {
+      "locked": {
+        "lastModified": 1737831083,
+        "narHash": "sha256-LJggUHbpyeDvNagTUrdhe/pRVp4pnS6wVKALS782gRI=",
+        "owner": "nix-community",
+        "repo": "impermanence",
+        "rev": "4b3e914cdf97a5b536a889e939fb2fd2b043a170",
+        "type": "github"
+      },
+      "original": {
+        "owner": "nix-community",
+        "repo": "impermanence",
+        "type": "github"
+      }
+    },
     "ixx": {
       "inputs": {
         "flake-utils": [
@@ -149,27 +164,12 @@
         "type": "github"
       }
     },
-    "preservation": {
-      "locked": {
-        "lastModified": 1738541138,
-        "narHash": "sha256-isT+jR8P8UFh5PJDzGHYXqVEHEZa0D5WvT5kfMf14AM=",
-        "owner": "nix-community",
-        "repo": "preservation",
-        "rev": "2f16754f9f6b766c1429375ab7417dc81cc90a63",
-        "type": "github"
-      },
-      "original": {
-        "owner": "nix-community",
-        "repo": "preservation",
-        "type": "github"
-      }
-    },
     "root": {
       "inputs": {
         "disko": "disko",
+        "impermanence": "impermanence",
         "nixpkgs": "nixpkgs",
         "nixvim": "nixvim",
-        "preservation": "preservation",
         "sops-nix": "sops-nix"
       }
     },
diff --git a/flake.nix b/flake.nix
index a65faaf..66b58a9 100644
--- a/flake.nix
+++ b/flake.nix
@@ -11,7 +11,7 @@
       url = "github:nix-community/disko";
       inputs.nixpkgs.follows = "nixpkgs";
     };
-    preservation.url = "github:nix-community/preservation";
+    impermanence.url = "github:nix-community/impermanence";
     sops-nix = {
       url = "github:Mic92/sops-nix";
       inputs.nixpkgs.follows = "nixpkgs";
@@ -24,7 +24,7 @@
       nixpkgs,
       nixvim,
       disko,
-      preservation,
+      impermanence,
       sops-nix,
       ...
     }:
@@ -53,7 +53,7 @@
                     ./hosts/${host}/state.nix
 
                     disko.nixosModules.disko
-                    preservation.nixosModules.preservation
+                    impermanence.nixosModules.impermanence
                     sops-nix.nixosModules.sops
                   ];
                 }
diff --git a/hosts/siit-dc/configuration.nix b/hosts/siit-dc/configuration.nix
index 7bf6696..51f8f3f 100644
--- a/hosts/siit-dc/configuration.nix
+++ b/hosts/siit-dc/configuration.nix
@@ -1,6 +1,6 @@
 { lib, ... }:
 {
-  preservation.enable = true;
+  environment.persistence."/persist".enable = true;
   swapDevices = lib.mkForce [ ];
   imports = [
     ../../shared/base.nix
diff --git a/shared/base.nix b/shared/base.nix
index ff352a6..f26da08 100644
--- a/shared/base.nix
+++ b/shared/base.nix
@@ -34,34 +34,23 @@
       ssss
     ];
 
-    ######################################## Preservation ###########################################
-    preservation = {
+    ######################################## Impermanence ###########################################
+    environment.persistence."/persist" = {
       enable = lib.mkDefault false;
-      preserveAt."/persist" = {
-        files = [
-          {
-            file = "/etc/machine-id";
-            inInitrd = true;
-          }
-          {
-            file = "/etc/ssh/ssh_host_rsa_key";
-            how = "symlink";
-            inInitrd = true; # sops-nix
-          }
-          {
-            file = "/etc/ssh/ssh_host_ed25519_key";
-            how = "symlink";
-            inInitrd = true; # sops-nix
-          }
-        ];
-        directories = [
-          "/var/lib/systemd/timers"
-          "/var/lib/nixos"
-          "/var/log"
-        ];
-      };
+      hideMounts = true;
+
+      files = [
+        "/etc/machine-id"
+        "/etc/ssh/ssh_host_rsa_key"
+        "/etc/ssh/ssh_host_ed25519_key"
+      ];
+
+      directories = [
+        "/var/lib/systemd/timers"
+        "/var/lib/nixos"
+        "/var/log"
+      ];
     };
-    systemd.suppressedSystemUnits = [ "systemd-machine-id-commit.service" ];
 
     ######################################## ZSH configuration ######################################
     users.defaultUserShell = pkgs.zsh;
diff --git a/shared/hardware/impermanence.nix b/shared/hardware/impermanence.nix
index a219ca5..26432ce 100644
--- a/shared/hardware/impermanence.nix
+++ b/shared/hardware/impermanence.nix
@@ -1,5 +1,7 @@
 { lib, ... }:
 {
+  fileSystems."/persist".neededForBoot = true;
+
   services.zfs = {
     autoScrub.enable = true;
     autoSnapshot = {