Traefik Loadbalancing multiple ports on the same container instance

Traefik Traefik v2
,
1

Hi all,
I have a docker container, where I host 10 tcp services, that are hosted on port 1000-1009. Now I want to create a load balancer using traefik, but I can't get it to work, routing the same load balancer to these 10 "servers" that are all running on the same instance.

The reason, why I want to run 10 services in a single container is, that a single instance of the server requires about 950 MB memory, and running 10 services in this instance only increases the memory usage to about 1 GB. If I would scale them up using Docker I would require 10 GB of Memory allocated, mostly for the environment. Also each of these services can only execute a single request at a time.

When I create my service with these labels:

  • "traefik.enable=true"
  • "traefik.tcp.routers.cas.rule=HostSNI(*)"
  • "traefik.tcp.routers.cas.entrypoints=cas"

it will only pick up the first exposed port of the container instance, like stated in the doc.

When I create multiple services

  • "traefik.tcp.routers.cas.rule=HostSNI(*)"
  • "traefik.tcp.routers.cas.entrypoints=cas"
  • "traefik.tcp.routers.cas.service=cas"
  • "traefik.tcp.services.cas.loadbalancer.server.port=1000"
  • "traefik.tcp.routers.cas2.rule=HostSNI(*)"
  • "traefik.tcp.routers.cas2.entrypoints=cas"
  • "traefik.tcp.routers.cas2.service=cas2"
  • "traefik.tcp.services.cas2.loadbalancer.server.port=1001"

It will just create multiple loadbalancers

image
image2849×363 33.3 KB

How can I create a loadbalancer with multiple ports, like this?

  • "traefik.tcp.routers.cas.rule=HostSNI(*)"
  • "traefik.tcp.routers.cas.entrypoints=cas"
  • "traefik.tcp.routers.cas.service=cas"
  • "traefik.tcp.services.cas.loadbalancer.server.port=1000-1009"

Also later I want to scale the docker instance aswell, so e.g. 10 replicas mean, that I have a loadbalancer loadbalancing to 100 service instances in 10 docker instances.

Best regards
Mosquito

2

Based on the documentation, it appears the docker provider doesn't support configuring services in the way you describe (but I could be wrong, @ldez can verify for me on this).

However, it is possible to configure Traefik through the File provider, https://docs.traefik.io/routing/services/#servers-load-balancer

tcp:
  services:
    my-service:
      loadBalancer:
        servers:
        - address: "<container-ip>:1000"
        - address: "<container-ip>:1001"
        - address: "<container-ip>:1002"
...
3

Hello,

@Mosquito you cannot use a range syntax.

In this case, you can use the file provider and the WRR https://docs.traefik.io/v2.2/routing/services/#weighted-round-robin-service to group your service: you have to define your services with labels and reference it in the WRR configuration.

4

Hi notsureifkevin, Idez,

thank you for the fast replies.
So as far as I understood, I will require these labels

  • "traefik.tcp.routers.cas.rule=HostSNI( * )"
  • "traefik.tcp.routers.cas.entrypoints=cas"
  • "traefik.tcp.routers.cas.service=cas"
  • "traefik.tcp.services.cas.loadbalancer.server.port=1000"
  • "traefik.tcp.routers.cas2.rule=HostSNI( * )"
  • "traefik.tcp.routers.cas2.entrypoints=cas"
  • "traefik.tcp.routers.cas2.service=cas2"
  • "traefik.tcp.services.cas2.loadbalancer.server.port=1001"
  • ... cas3 (port 1002)
  • ... cas4 (port 1003)
  • ... cas5-10

and then just create a weighted round robin over all services with the same weight.

[tcp.services]
[tcp.services.app]
[[tcp.services.app.weighted.services]]
name = "cas1"
weight = 1
[[tcp.services.app.weighted.services]]
name = "cas2"
weight = 1
[[tcp.services.app.weighted.services]]
name = "cas3"
weight = 1
... cas 4-10

Okay I will try that. Thank you!