I followed the instructions:
However, when a container is created on that host it still cannot be reached by containers on another host.
EX. I started an es cluster and my es-masters landed on the rancher-server host, as a result the clients and data nodes can’t connect to the masters. How can I get the containers on the rancher-server to connect to the other containers?
Have you looked at our troubleshooting FAQs? Looking at your post now, it makes me realize I should have pointed it out in the training. 
http://docs.rancher.com/rancher/faqs/troubleshooting/
Hopefully that should help you troubleshoot why your communication across hosts aren’t working.
I did get it figured out. I was trying to use multicast to discover the containers, once i used unicast it worked perfectly.