How to fix the issue "Filtering container with empty frontend rule" when running Traefik in Docker Swarm

Question

Traefik is not creating the front-ends nor the back-ends when running in a Docker Swarm cluster with more than one machine.

I created a Docker Swarm on my MacBook (OS version: 10.14.2 (18C54)) by following this tutorial: https://docs.docker.com/get-started/part4/. The docker-machine on my laptop has the version 0.14.0, build 89b8332 and the docker engine running on the VMs has the version 18.09.1, build 4c52b90. Here's a summary of the machines created:

Once the machines were up and running and the swarm was created, I deployed the following stack in my swarm:

version: '3.4'

services:
  api_gateway:
    image: traefik
    command: --api \
      --docker \
      --docker.swarmmode \
      --docker.watch \
      --logLevel=DEBUG
    ports:
      - "80:80"
      - "443:443"
      - "8080:8080"
    volumes:
      - /var/run/docker.sock:/var/run/docker.sock
    networks:
      - external
      - internal
    deploy:
      placement:
        constraints: [node.role==manager]
  redis:
    image: redis:latest
    command: ["redis-server", "--appendonly", "yes"]
    volumes:
      - redis:/data
    networks:
      - internal
    deploy:
      placement:
        constraints: [node.role==worker]
  nginx-test:
    image: valian/nginx-test-page
    labels:
      - "traefik.frontend.rule=Host:api.local.mydomain.com"
    depends_on:
      - redis
    networks:
      - external
      - internal
    deploy:
      placement:
        constraints: [node.role==worker]
networks:
  external:
    driver: overlay
    external: true
  internal:
    driver: overlay
volumes:
  redis:

The screenshot below shows the services running and the cluster visualizer for the swarm:

As far as I understand, Traefik should have discovered the service nginx-test, then created the front-end and back-end for it. Here's a scrennshot of the Traefik dashboard:

It seems that the api_gateway service (Traefik) is not able to identify the frontend rule defined for the nginx-test service, as you can on the log below:

2019-02-06T09:04:37.139463121Z time="2019-02-06T09:04:37Z" level=debug msg="Filtering container with empty frontend rule webserver_nginx-test.1 "

Am I missing something on the Traefik setup? Is there another way to set it up when running the reverse proxy in a Docker Swarm cluster?

Answer 1

With Swarm, the labels section must define in the deploy section.

https://docs.traefik.io/configuration/backends/docker/#using-docker-with-swarm-mode

version: "3"
services:
  whoami:
    deploy:
      labels:
        traefik.docker.network: traefik