Does traefik know docker-compose service names?

Traefik Traefik v2
1

How exactly does Traefik talk to docker services when they're defined in a docker-compose file? For example, if you have two identical docker-compose files - except they have separate external networks - then is there any way Traefik could get confused about which is which? In my testing it does seem like it... Perhaps each docker-compose file needs to have unique service names, despite each service getting unique IPs in docker's networking - and also despite each docker-compose project being isolated via COMPOSE_PROJECT_NAME variable.

@ldez Hoping you know the answer to this :slight_smile:

2

Found someone with a similar issue, but my config is just like theirs and they are not getting this error (detailed below):

3

Figured it out! I had - "traefik.docker.network:${NETWORK}"
instead of
- "traefik.docker.network=${NETWORK}"
in a few places. Would be great if that syntax failed instead of being sent to traefik & misinterpreted.

Now I just need to figure out how to get traefik docker labels to work during docker-compose build time:

The following does not work:

    app:
      container_name: "app-${COMPOSE_PROJECT_NAME}"
      image: "app"
      restart: always
      build:
        context: .
        network: "${NETWORK}"
        args:
         - project=$COMPOSE_PROJECT_NAME
 #      labels:
 #        - "traefik.enable=true"
 #        - "traefik.port=3000"
 #        - "traefik.docker.network=${NETWORK}"

Those layers get built into the image and do not supply treafik with the information it needs.

4

So basically app needs to be taken offline before the build time networking will work now... Perhaps there is some networking for 'app' hanging around between builds. I tried giving it a different network (a build_time_network), but still traefik seems to grab it due to the fact that app is around running. This problem will get fixed when I start doing builds on a separate system, but it would be nice to be able to change traefik.docker.network during build: context vs the services label: context.