Customize your horizon deployment in /etc/openstack_deploy/user_variables.yml.
The OpenStack-Ansible project provides the ability to secure Dashboard (horizon) communications with self-signed or user-provided SSL certificates.
Refer to Securing services with SSL certificates for available configuration options.
OpenStack-Ansible supports deployment of a horizon customization module. After building your customization module, configure the horizon_customization_module variable with a path to your module.
horizon_customization_module: /path/to/customization_module.py