feat: docker for pi hole

hosts/karasumaru/configuration.nix

@@ -6,7 +6,9 @@
   lib,
   pkgs,
   ...
-}: {
+}: let
+  serverIP = 0.0 .0 .0;
+in {
   imports = [
     # Include the results of the hardware scan.
     ./hardware-configuration.nix
@@ -35,5 +37,32 @@
     };
   };
 
+  virtualisation.docker.enable = true;
+  virtualisation.oci-containers = {
+    backend = "docker";
+    virtualisation.oci-containers.containers.pihole = {
+      image = "pihole/pihole:latest";
+      ports = [
+        "${serverIP}:53:53/tcp"
+        "${serverIP}:53:53/udp"
+        "3080:80"
+        "30443:443"
+      ];
+      volumes = [
+        "/var/lib/pihole/:/etc/pihole/"
+        "/var/lib/dnsmasq.d:/etc/dnsmasq.d/"
+      ];
+      environment = {
+        ServerIP = serverIP;
+      };
+      extraOptions = [
+        "--cap-add=NET_ADMIN"
+        "--dns=127.0.0.1"
+        "--dns=1.1.1.1"
+      ];
+      workdir = "/var/lib/pihole/";
+    };
+  };
+
   system.stateVersion = "24.11";
 }