diff --git a/services/hydra-build.nix b/services/hydra-build.nix
index add6631..43ccdce 100644
--- a/services/hydra-build.nix
+++ b/services/hydra-build.nix
@@ -11,22 +11,32 @@ mkIf flags.hydra-builder {
 
   # Paquets
   environment.systemPackages = with pkgs; [
-    qemu
     kvm
+    qemu
+    virtualbox
   ];
 
   # Services
 
   ## Services de virtualisation utilisé pour les tests hydra
-  virtualisation.docker.enable = true;
-  virtualisation.libvirtd.enable = true;
-  virtualisation.libvirtd.enableKVM = true;
-  #virtualisation.virtualbox.guest.enable = true;
-  virtualisation.virtualbox.host.enable = true;
-  virtualisation.virtualbox.host.headless = true;
+  virtualisation = {
+    docker.enable = true;
+    libvirtd = {
+      enable = true;
+      enableKVM = true;
+    };
+    virtualbox = {
+      #guest.enable = true;
+      host.enable = true;
+      host.headless = true;
+    };
+  };
 
-  ## Ménage automatique tous les jours
-  nix.gc.automatic = true;
+  ## Ménage automatique tous les jours - Frequent garbage collection is a good idea for build machines.
+  nix.gc = {
+    automatic = true;
+    dates = "*:0/30";
+  };
 
   # users.users."hydrabld" = {
   #   description = "Execution des jobs hydra";