Two stacks behind traefik https://docs.traefik.io/user-guide/swarm-mode/

docker-compose-1.yml

version: "3"
services:
  web:
    image: emilevauge/whoami
    networks:
      - default
      - traefik-net
    deploy:
      labels:
        - "traefik.port=80"
        - "traefik.docker.network=traefik-net"
        - "traefik.frontend.rule=Host:whoamistack1.traefik.local"
networks:
  traefik-net:
    external: true

docker-compose-2.yml

version: "3"
services:
  web:
    image: emilevauge/whoami
    networks:
      - default
      - traefik-net
    deploy:
      labels:
        - "traefik.port=80"
        - "traefik.docker.network=traefik-net"
        - "traefik.frontend.rule=Host:whoamistack2.traefik.local"
networks:
  traefik-net:
    external: true

run-traefik

$ docker network create --driver=overlay traefik-net
$ docker service create \
    --name traefik \
    --constraint=node.role==manager \
    --publish 80:80 --publish 8080:8080 \
    --mount type=bind,source=/var/run/docker.sock,target=/var/run/docker.sock \
    --network traefik-net \
    traefik \
    --docker \
    --docker.swarmMode \
    --docker.domain=traefik \
    --docker.watch \
    --api