How to fix Traefik Could not define the service name for the router: too many services

Problem:

Traefik does not load some of your services and you see an error message like the following one:

traefik_1  | time="2022-03-27T15:22:05Z" level=error msg="Could not define the service name for the router: too many services" routerName=myapp providerName=docker

with a docker label config with multiple routers like this:

labels:
    - "traefik.enable=true"
    - "traefik.http.routers.myapp-console.rule=Host(`console.myapp.mydomain.com`)"
    - "traefik.http.routers.myapp-console.entrypoints=websecure"
    - "traefik.http.routers.myapp-console.tls.certresolver=alpn"
    - "traefik.http.services.myapp-console.loadbalancer.server.port=9001"
    #
    - "traefik.http.routers.myapp.rule=Host(`myapp.mydomain.com`)"
    - "traefik.http.routers.myapp.entrypoints=websecure"
    - "traefik.http.routers.myapp.tls.certresolver=cloudflare-techoverflow"
    - "traefik.http.routers.myapp.tls.domains[0].main=mydomain.com"
    - "traefik.http.routers.myapp.tls.domains[0].sans=*.mydomain.com"
    - "traefik.http.services.myapp.loadbalancer.server.port=9000"

Solution

The basic issue here is that you have multiple routers defined for a single docker container and Traefik does not know which http.services belongs to which http.routers!

In order to fix this, explicitly tell traefik for each router what service it should use like this:

- "traefik.http.routers.myapp-console.service=myapp-console"

Full example:

labels:
    - "traefik.enable=true"
    - "traefik.http.routers.myapp-console.rule=Host(`console.myapp.mydomain.com`)"
    - "traefik.http.routers.myapp-console.entrypoints=websecure"
    - "traefik.http.routers.myapp-console.tls.certresolver=alpn"
    - "traefik.http.routers.myapp-console.service=myapp-console"
    - "traefik.http.services.myapp-console.loadbalancer.server.port=9001"
    #
    - "traefik.http.routers.myapp.rule=Host(`myapp.mydomain.com`)"
    - "traefik.http.routers.myapp.entrypoints=websecure"
    - "traefik.http.routers.myapp.tls.certresolver=cloudflare-techoverflow"
    - "traefik.http.routers.myapp.tls.domains[0].main=mydomain.com"
    - "traefik.http.routers.myapp.tls.domains[0].sans=*.mydomain.com"
    - "traefik.http.routers.myapp.service=myapp"
    - "traefik.http.services.myapp.loadbalancer.server.port=9000"