okd/roles/openshift_openstack/tasks/net_vars_check.yaml

---
- name: Check the provider network configuration
  fail:
    msg: "Flannel SDN requires a dedicated containers data network and can not work over a provider network"
  when:
    - openshift_openstack_provider_network_name is defined
    - openstack_private_data_network_name is defined

- name: Check the flannel network configuration
  fail:
    msg: "A dedicated containers data network is only supported with Flannel SDN"
  when:
    - openstack_private_data_network_name is defined
    - not openshift_use_flannel|default(False)|bool