Neutron must be configured to notify Nova of network topology changes. On the controller node, update the [nova] section of the Neutron configuration file located at /etc/neutron/neutron.conf with the following settings:

[nova] 
... 
auth_url = http://controller01:35357 
auth_type = password 
project_domain_name = default 
user_domain_name = default 
region_name = RegionOne 
project_name = service 
username = nova 
password = nova