diff --git a/playbooks/bootstrap-bridge.yaml b/playbooks/bootstrap-bridge.yaml
index 13014ef9bf..a0f9f87983 100644
--- a/playbooks/bootstrap-bridge.yaml
+++ b/playbooks/bootstrap-bridge.yaml
@@ -66,6 +66,6 @@
           /home/zuul/src/opendev.org/opendev/system-config/playbooks/zuul/run-production-bootstrap-bridge-add-rootkey.yaml
           > /var/log/ansible/install-root-key.{{ lookup('pipe', 'date +%Y-%m-%dT%H:%M:%S') }}.log 2>&1
       environment:
-        ROOT_RSA_KEY: '{{ "-e @/home/zuul/root-rsa-key.json" if root_rsa_key else "" }}'
+        ROOT_RSA_KEY: '{{ "-e @/home/zuul/root-rsa-key.json" if root_rsa_key is defined else "" }}'
         ANSIBLE_ROLES_PATH: '/home/zuul/src/opendev.org/opendev/system-config/playbooks/roles'
       no_log: true