Get parameter from instance and use it in heat template function
I am using Mitaka Openstack on Ubuntu. I want to assign a floating IP to OpenStack instance with heat template. On my instance, there is a configuration file (such as /tmp/ip.txt) like this ;
[root@instance-1 ~] cat /root/ip.txt
floating_ip="172.24.3.225"
I want to get the IP address from this file, then use as a floating IP and associate to my instance. How can I get the IP address which is written on my configuration file with heat template? Is there a way to get parameter from instance via cloud-init? And also, is it possible to use this parameter ($floating_ip) with "OS::Neutron::FloatingIP" resource?