Comment 3 for bug 1812864

The reason for adding https://review.openstack.org/#/c/566361/ is that it is passed to instances by heat for calling back to the heat API. Instances can't be assumed to have access to the internal API, so we need to pass the external URL.

I can see why this causes issues with external TLS enabled however, since the container won't necessarily have the necessary certificates trusted. The workaround posted above should work.