According to RFC 5737, https://tools.ietf.org/html/rfc5737, IPv4 Address Blocks Reserved for Documentation, 192.0.2.0/24, 198.51.100.0/24 or 203.0.113.0/24 should be used in documentation.
These networks should be blocked by Internet Service Providers so they do not appear on public Internet. Openstack ansible is using "1.2.3.4" as example for a public address. 1.2.3.4 is routable on public Internet.
./etc/openstack_deploy/user_variables.yml.prod.example:haproxy_keepalived_external_vip_cidr: "1.2.3.4/32"
./etc/openstack_deploy/user_variables.yml.prod-ceph.example:haproxy_keepalived_external_vip_cidr: "1.2.3.4/32"
It also exist in documentation examples on
https://docs.openstack.org/openstack-ansible/latest/user/prod/example.html
https://docs.openstack.org/openstack-ansible/queens/user/prod/example.html
https://docs.openstack.org/openstack-ansible/latest/user/l3pods/example.html
https://docs.openstack.org/openstack-ansible/queens/user/l3pods/example.html
https://docs.openstack.org/openstack-ansible/latest/user/ceph/full-deploy.html
https://docs.openstack.org/openstack-ansible/queens/user/ceph/full-deploy.html
My suggestion for solution is to change haproxy_keepalived_external_vip_cidr into something like "<external_ip_address>/32" and making sure it fails at runtime if the user forgets to specify a correct IPv4 or IPv6 address.
Fix proposed to branch: master
Review: https:/