The platforms we plan to run on our cloud are generally web-based, and each listening on their own unique TCP port. When a container in a swarm exposes a port, then connecting to any swarm member on that port will result in your request being forwarded to the appropriate host running the container. (Docker calls this the swarm "routing mesh")
This is a companion discussion topic for the original entry at https://geek-cookbook.funkypenguin.co.nz/docker-swarm/traefik/