diff --git a/_config/routes.yml b/_config/routes.yml
index 65ef08e18..fda36ecab 100644
--- a/_config/routes.yml
+++ b/_config/routes.yml
@@ -21,3 +21,5 @@ After:
 SilverStripe\Control\Director:
   rules:
     'admin': 'SilverStripe\Admin\AdminRootController'
+  must_use_primary_db_rules:
+    - admin