Comment 1 for bug 1702706

As per documentation you need to register the endpoint using the CONTROLLER_IP or a dns name that the vms can find route to.

http://git.openstack.org/cgit/openstack/magnum/tree/install-guide/source/common/prerequisites.rst?h=stable%2Focata#n141

Please check this note too:
http://git.openstack.org/cgit/openstack/magnum/tree/install-guide/source/install.rst?h=stable/ocata#n41

I need to update it to mention that, keystone, nova, heat and magnum must be reachable from the vms.