treewide: initial commit

2026-04-18 16:28:25 -04:00
commit 75532a931c
18 changed files with 1237 additions and 0 deletions
@@ -0,0 +1,94 @@
+{
+  config,
+  lib,
+  pkgs,
+  ...
+}:
+{
+  boot.initrd.systemd = {
+    extraBin = {
+      "mkdir" = "${pkgs.coreutils}/bin/mkdir";
+      "date" = "${pkgs.coreutils}/bin/date";
+      "stat" = "${pkgs.coreutils}/bin/stat";
+      "mv" = "${pkgs.coreutils}/bin/mv";
+      "find" = lib.getExe pkgs.findutils;
+      "btrfs" = lib.getExe pkgs.btrfs-progs;
+    };
+
+    services.impermanence-btrfs-rolling-root = {
+      unitConfig.DefaultDependencies = false;
+      serviceConfig.Type = "oneshot";
+
+      requiredBy = [ "initrd.target" ];
+      before = [ "sysroot.mount" ];
+      requires = [ "initrd-root-device.target" ];
+      after = [
+        "initrd-root-device.target"
+        "local-fs-pre.target"
+      ];
+
+      script = ''
+        mkdir /impermanence_tmp
+        mount /dev/disk/by-label/${config.host.name} /impermanence_tmp || mount /dev/disk/by-label/NIXOS_SD /impermanence_tmp
+
+        timestamp=$(date --date="@$(stat -c %Y /impermanence_tmp/@)" "+%Y-%m-%d_%H:%M:%S")
+        if [[ -e /impermanence_tmp/@ ]]; then
+            mkdir -p /impermanence_tmp/roots
+            mv /impermanence_tmp/@ "/impermanence_tmp/roots/$timestamp"
+        fi
+
+        delete_subvolume_recursively() {
+            IFS=$'\n'
+            for i in $(btrfs subvolume list -o "$1" | cut -f 9- -d ' '); do
+                delete_subvolume_recursively "/impermanence_tmp/$i"
+            done
+            btrfs subvolume delete "$1"
+        }
+
+        for i in $(find /impermanence_tmp/roots/ -maxdepth 1 -mtime +30); do
+            delete_subvolume_recursively "$i"
+        done
+
+        btrfs subvolume create /impermanence_tmp/@
+        umount /impermanence_tmp
+      '';
+    };
+  };
+
+  fileSystems."/persist".neededForBoot = true;
+
+  environment.persistence."/persist" = {
+    enable = true;
+    hideMounts = true;
+
+    directories = [
+      "/etc/ssh"
+      "/export"
+      "/mnt"
+      "/var/db/sudo/lectured"
+      "/var/lib/nfs"
+      "/var/lib/nixos"
+      "/var/lib/systemd/coredump"
+      "/var/log"
+    ];
+    files = [
+      "/etc/machine-id"
+    ];
+  };
+
+  services.openssh.hostKeys =
+    let
+      statePath = config.environment.persistence."/persist".persistentStoragePath + "/etc/ssh";
+    in
+    [
+      {
+        path = statePath + "/ssh_host_rsa_key";
+        type = "rsa";
+        bits = 4096;
+      }
+      {
+        path = statePath + "/ssh_host_ed25519_key";
+        type = "ed25519";
+      }
+    ];
+}