chore(ovn): use gateway_ip=null
diff --git a/roles/octavia/tasks/generate_resources.yml b/roles/octavia/tasks/generate_resources.yml
index 58ff548..cd8dfaf 100644
--- a/roles/octavia/tasks/generate_resources.yml
+++ b/roles/octavia/tasks/generate_resources.yml
@@ -26,6 +26,7 @@
     network_name: "{{ octavia_management_network_name }}"
     name: "{{ octavia_management_subnet_name }}"
     cidr: "{{ octavia_management_subnet_cidr }}"
+    gateway_ip: null
 
 - name: Create health manager security group
   openstack.cloud.security_group: