diff --git a/zuul.d/zuul-legacy-jobs.yaml b/zuul.d/zuul-legacy-jobs.yaml
index 1855f133..23cce585 100644
--- a/zuul.d/zuul-legacy-jobs.yaml
+++ b/zuul.d/zuul-legacy-jobs.yaml
@@ -7067,6 +7067,7 @@
     name: legacy-periodic-gitdm
     parent: legacy-base
     run: playbooks/legacy/periodic-gitdm/run
+    branches: master
     timeout: 1800
 
 - job: