diff --git a/ansible/overcloud-introspection-rules.yml b/ansible/overcloud-introspection-rules.yml
index f97bb67c3..2fbcc142b 100644
--- a/ansible/overcloud-introspection-rules.yml
+++ b/ansible/overcloud-introspection-rules.yml
@@ -49,6 +49,6 @@
       # These variables may be referenced in the introspection rules.
       inspector_rule_var_ipmi_username: "{{ inspector_ipmi_username }}"
       inspector_rule_var_ipmi_password: "{{ inspector_ipmi_password }}"
-      inspector_rule_var_lldp_switch_port_interface: "{{ inspector_lldp_switch_port_interface_default }}"
+      inspector_rule_var_lldp_switch_port_interface: "{{ inspector_lldp_switch_port_interface_default or '' }}"
       inspector_rule_var_deploy_kernel: "{{ ipa_kernel_id.stdout }}"
       inspector_rule_var_deploy_ramdisk: "{{ ipa_ramdisk_id.stdout }}"
diff --git a/ansible/seed-introspection-rules.yml b/ansible/seed-introspection-rules.yml
index 1759e70a3..8d2f98a44 100644
--- a/ansible/seed-introspection-rules.yml
+++ b/ansible/seed-introspection-rules.yml
@@ -12,6 +12,6 @@
       # These variables may be referenced in the introspection rules.
       inspector_rule_var_ipmi_username: "{{ kolla_bifrost_inspector_ipmi_username }}"
       inspector_rule_var_ipmi_password: "{{ kolla_bifrost_inspector_ipmi_password }}"
-      inspector_rule_var_lldp_switch_port_interface: "{{ kolla_bifrost_inspector_lldp_switch_port_interface }}"
+      inspector_rule_var_lldp_switch_port_interface: "{{ kolla_bifrost_inspector_lldp_switch_port_interface or '' }}"
       inspector_rule_var_deploy_kernel: "{{ kolla_bifrost_inspector_deploy_kernel }}"
       inspector_rule_var_deploy_ramdisk: "{{ kolla_bifrost_inspector_deploy_ramdisk }}"