What does "loadbalancer.server.url" really mean?

Traefik Traefik v3 (latest)
1

Hi all,

I use traefik since one year and I understand pretty well how it works.

What I really do not understand is what does it really mean loadbalancer.server.url.

I setup several container with traefik settings described by labels. Here an example:

    traefik.enable: true
    traefik.http.routers.[service].entrypoints: websecure 
    traefik.http.routers.[service].rule: Host(`sub.example.com`)
    traefik.http.routers.[service].tls: true
    traefik.http.routers.[service].tls.certresolver: production
    # traefik.http.services.[service].loadbalancer.server.url: '192.168.32.13:80'
    traefik.http.services.[service].loadbalancer.server.port: 8090
    traefik.docker.network: traefik

In this example I understand that declaring server.port, I'm telling to traefik in with port of my container he should forward the traffic.

Now the questions about loadbalancer.server.url:

  • What it really means?
  • Is the server address an real ip address of my local network (yes, I setup a perfectly working home server with apis, webserver and so on)
  • Is the server address the address assign by docker in traefik internal network?

And now the big deals:

Ho can I forward specific domain traffic into a container that is used as VPN server?
My big deal is to forward the specific subdomain traffic (eg. test.example.com) to a device (peer) connected with the VPN server container.

I understand it's a complicated task. My first goal is to understand "loadbalancer.server.url" meaning.
Second goal is how to debug properly (or sniff, or have logs) of the traffic related to a domain.
Third goal, if someone has knowledge to my big deal problem, well... you're awesome!

2

Dynamic config on containers via labels always has the container itself as target.

loadbalancer.servers.url is used in dynamic config file to indicate the target URL/IP (doc).

Today it can actually not be used in Docker labels, it needs to be in an extra file. You can support the issue by adding your like.

4

Ok now i understand better.

So, accordingly on what you wrote, server.url what represent?
Container IP in traefik network or LAN device ip?

5

It can be anything you can reach from within your Traefik container: domain, local IP, remote IP, even external IP.