SSL for Murano API service can be configured in ssl section in /etc/murano-api/murano-api.conf. Just point to a valid SSL certificate. See the example below:

cert_file = PATH
key_file = PATH
ca_file = PATH

The use of SSL is automatically started after point to HTTPS protocol instead of HTTP during registration Murano API service in endpoints (Change publicurl argument to start with https://). See here how to register Murano API in Openstack Keystone.

SSL for Murano API is implemented like in any other Openstack component. This realization is based on ssl python module so more information about it can be found here.