diff --git a/ops/nixos/marukuru/default.nix b/ops/nixos/marukuru/default.nix
index f98acc8180..04812bfa50 100644
--- a/ops/nixos/marukuru/default.nix
+++ b/ops/nixos/marukuru/default.nix
@@ -143,6 +143,8 @@ in {
           gitlab_rails['smtp_port'] = 25
           gitlab_rails['gitlab_email_from'] = 'heptapod@hg.lukegb.com'
           gitlab_rails['gitlab_email_reply_to'] = 'noreply@hg.lukegb.com'
+
+          prometheus['enable'] = false
         '';
       };
     };