Running Non Containerized Nginx and Apps Outside of Rancher Environment on a Host

I have a Ubuntu 16 instance on AWS which is running an nginx reverse proxy (from port 80) to a simple frontend server running on a standard port 8000++.

I connected this host to my rancher server (which is on a separate machine) and ran a simple stack with some services inside the rancher host. I never mapped to port 80 inside any of these services. For some reason, the act of doing this made the rancher host “take over” my nginx reverse proxy (which has always been running outside of the rancher environment). My nginx reverse proxy stopped working entirely and any URLs we pointed to the instance’s IP address would just land on the Rancher services basic landing page.

We tried to read the nginx logs and what not and could not find anything.

I wanted to ask if this is the expected behavior and whether it is good practice to run a Rancher host and other apps outside of the Rancher environment on the same machine? For example, could I set up my “outside nginx” to reverse proxy to both a frontend server outside of rancher as well proxy to running rancher services inside the rancher network?

If anyone can point to any documentation detailing what happens when a rancher host is connected and what it does to the base machine’s outside facing network, that would be really appreciated!