diff --git a/nixos/modules/system/boot/systemd/nspawn.nix b/nixos/modules/system/boot/systemd/nspawn.nix
index 11fbb88838e1..e9bf82c462a9 100644
--- a/nixos/modules/system/boot/systemd/nspawn.nix
+++ b/nixos/modules/system/boot/systemd/nspawn.nix
@@ -127,6 +127,9 @@ in {
         })
         {
           systemd.targets.multi-user.wants = [ "machines.target" ];
+          systemd.services."systemd-nspawn@".environment = {
+            SYSTEMD_NSPAWN_UNIFIED_HIERARCHY = mkDefault "1";
+          };
         }
       ];
 }