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Traefik & Docker

A Story of Labels & Containers

Docker

Attach labels to your containers and let Traefik do the rest!

Configuration Examples

Configuring Docker & Deploying / Exposing Services

Enabling the docker provider

[providers.docker]
providers:
  docker: {}
--providers.docker=true

Attaching labels to containers (in your docker compose file)

version: "3"
services:
  my-container:
    # ...
    labels:
      - traefik.http.routers.my-container.rule=Host(`mydomain.com`)
Configuring Docker Swarm & Deploying / Exposing Services

Enabling the docker provider (Swarm Mode)

[providers.docker]
  # swarm classic (1.12-)
  # endpoint = "tcp://127.0.0.1:2375"
  # docker swarm mode (1.12+)
  endpoint = "tcp://127.0.0.1:2377"
  swarmMode = true
providers:
  docker:
    # swarm classic (1.12-)
    # endpoint = "tcp://127.0.0.1:2375"
    # docker swarm mode (1.12+)
    endpoint: "tcp://127.0.0.1:2375"
    swarmMode: true
--providers.docker.endpoint="tcp://127.0.0.1:2375"
--providers.docker.swarmMode=true

Attach labels to services (not to containers) while in Swarm mode (in your docker compose file)

version: "3"
services:
  my-container:
    deploy:
      labels:
        - traefik.http.routers.my-container.rule=Host(`mydomain.com`)
        - traefik.http.services.my-container-service.loadbalancer.server.port=8080

Labels in Docker Swarm Mode

While in Swarm Mode, Traefik uses labels found on services, not on individual containers. Therefore, if you use a compose file with Swarm Mode, labels should be defined in the deploy part of your service. This behavior is only enabled for docker-compose version 3+ (Compose file reference).

Routing Configuration

Labels

  • Labels are case insensitive.
  • The complete list of labels can be found in the reference page.

General

Traefik creates, for each container, a corresponding service and router.

The Service automatically gets a server per instance of the container, and the router automatically gets a rule defined by defaultRule (if no rule for it was defined in labels).

Service definition

In general when configuring a Traefik provider, a service assigned to one (or several) router(s) must be defined as well for the routing to be functional.

There are, however, exceptions when using label-based configurations:

  1. If a label defines a router (e.g. through a router Rule) and a label defines a service (e.g. implicitly through a loadbalancer server port value), but the router does not specify any service, then that service is automatically assigned to the router.
  2. If a label defines a router (e.g. through a router Rule) but no service is defined, then a service is automatically created and assigned to the router.

As one would expect, in either of these cases, if in addition a service is specified for the router, then that service is the one assigned, regardless of whether it actually is defined or whatever else other services are defined.

Automatic service assignment with labels

With labels in a compose file

labels:
  - "traefik.http.routers.myproxy.rule=Host(`foo.com`)"
  # service myservice gets automatically assigned to router myproxy
  - "traefik.http.services.myservice.loadbalancer.server.port=80"
Automatic service creation and assignment with labels

With labels in a compose file

labels:
  # no service specified or defined and yet one gets automatically created
  # and assigned to router myproxy.
  - "traefik.http.routers.myproxy.rule=Host(`foo.com`)"

Routers

To update the configuration of the Router automatically attached to the container, add labels starting with traefik.http.routers.<name-of-your-choice>. and followed by the option you want to change.

For example, to change the rule, you could add the label traefik.http.routers.my-container.rule=Host(`mydomain.com`).

traefik.http.routers.<router_name>.rule

See rule for more information.

- "traefik.http.routers.myrouter.rule=Host(`mydomain.com`)"
traefik.http.routers.<router_name>.entrypoints

See entry points for more information.

- "traefik.http.routers.myrouter.entrypoints=web,websecure"
traefik.http.routers.<router_name>.middlewares

See middlewares and middlewares overview for more information.

- "traefik.http.routers.myrouter.middlewares=auth,prefix,cb"
traefik.http.routers.<router_name>.service

See rule for more information.

- "traefik.http.routers.myrouter.service=myservice"
traefik.http.routers.<router_name>.tls

See tls for more information.

- "traefik.http.routers.myrouter.tls=true"
traefik.http.routers.<router_name>.tls.certresolver

See certResolver for more information.

- "traefik.http.routers.myrouter.tls.certresolver=myresolver"
traefik.http.routers.<router_name>.tls.domains[n].main

See domains for more information.

- "traefik.http.routers.myrouter.tls.domains[0].main=foobar.com"
traefik.http.routers.<router_name>.tls.domains[n].sans

See domains for more information.

- "traefik.http.routers.myrouter.tls.domains[0].sans=test.foobar.com,dev.foobar.com"
traefik.http.routers.<router_name>.tls.options

See options for more information.

- "traefik.http.routers.myrouter.tls.options=foobar"
traefik.http.routers.<router_name>.priority

See options for more information.

- "traefik.http.routers.myrouter.priority=42"

Services

To update the configuration of the Service automatically attached to the container, add labels starting with traefik.http.services.<name-of-your-choice>., followed by the option you want to change.

For example, to change the passHostHeader behavior, you'd add the label traefik.http.services.<name-of-your-choice>.loadbalancer.passhostheader=false.

traefik.http.services.<service_name>.loadbalancer.server.port

Registers a port. Useful when the container exposes multiples ports.

Mandatory for Docker Swarm.

- "traefik.http.services.myservice.loadbalancer.server.port=8080"
traefik.http.services.<service_name>.loadbalancer.server.scheme

Overrides the default scheme.

- "traefik.http.services.myservice.loadbalancer.server.scheme=http"
traefik.http.services.<service_name>.loadbalancer.passhostheader

See pass Host header for more information.

- "traefik.http.services.myservice.loadbalancer.passhostheader=true"
traefik.http.services.<service_name>.loadbalancer.healthcheck.headers.<header_name>

See health check for more information.

- "traefik.http.services.myservice.loadbalancer.healthcheck.headers.X-Foo=foobar"
traefik.http.services.<service_name>.loadbalancer.healthcheck.hostname

See health check for more information.

- "traefik.http.services.myservice.loadbalancer.healthcheck.hostname=foobar.com"
traefik.http.services.<service_name>.loadbalancer.healthcheck.interval

See health check for more information.

- "traefik.http.services.myservice.loadbalancer.healthcheck.interval=10"
traefik.http.services.<service_name>.loadbalancer.healthcheck.path

See health check for more information.

- "traefik.http.services.myservice.loadbalancer.healthcheck.path=/foo"
traefik.http.services.<service_name>.loadbalancer.healthcheck.port

See health check for more information.

- "traefik.http.services.myservice.loadbalancer.healthcheck.port=42"
traefik.http.services.<service_name>.loadbalancer.healthcheck.scheme

See health check for more information.

- "traefik.http.services.myservice.loadbalancer.healthcheck.scheme=http"
traefik.http.services.<service_name>.loadbalancer.healthcheck.timeout

See health check for more information.

- "traefik.http.services.myservice.loadbalancer.healthcheck.timeout=10"
traefik.http.services.<service_name>.loadbalancer.sticky

See sticky sessions for more information.

- "traefik.http.services.myservice.loadbalancer.sticky=true"
traefik.http.services.<service_name>.loadbalancer.sticky.cookie.httponly

See sticky sessions for more information.

- "traefik.http.services.myservice.loadbalancer.sticky.cookie.httponly=true"
traefik.http.services.<service_name>.loadbalancer.sticky.cookie.name

See sticky sessions for more information.

- "traefik.http.services.myservice.loadbalancer.sticky.cookie.name=foobar"
traefik.http.services.<service_name>.loadbalancer.sticky.cookie.secure

See sticky sessions for more information.

- "traefik.http.services.myservice.loadbalancer.sticky.cookie.secure=true"
traefik.http.services.<service_name>.loadbalancer.responseforwarding.flushinterval

See response forwarding for more information.

- "traefik.http.services.myservice.loadbalancer.responseforwarding.flushinterval=10"

Middleware

You can declare pieces of middleware using labels starting with traefik.http.middlewares.<name-of-your-choice>., followed by the middleware type/options.

For example, to declare a middleware redirectscheme named my-redirect, you'd write traefik.http.middlewares.my-redirect.redirectscheme.scheme=https.

More information about available middlewares in the dedicated middlewares section.

Declaring and Referencing a Middleware
   services:
     my-container:
       # ...
       labels:
         # Declaring a middleware
         - traefik.http.middlewares.my-redirect.redirectscheme.scheme=https
         # Referencing a middleware
         - traefik.http.routers.my-container.middlewares=my-redirect

Conflicts in Declaration

If you declare multiple middleware with the same name but with different parameters, the middleware fails to be declared.

TCP

You can declare TCP Routers and/or Services using labels.

Declaring TCP Routers and Services
   services:
     my-container:
       # ...
       labels:
         - "traefik.tcp.routers.my-router.rule=HostSNI(`my-host.com`)"
         - "traefik.tcp.routers.my-router.tls=true"
         - "traefik.tcp.services.my-service.loadbalancer.server.port=4123"

TCP and HTTP

If you declare a TCP Router/Service, it will prevent Traefik from automatically creating an HTTP Router/Service (like it does by default if no TCP Router/Service is defined). You can declare both a TCP Router/Service and an HTTP Router/Service for the same container (but you have to do so manually).

TCP Routers

traefik.tcp.routers.<router_name>.entrypoints

See entry points for more information.

- "traefik.tcp.routers.mytcprouter.entrypoints=ep1,ep2"
traefik.tcp.routers.<router_name>.rule

See rule for more information.

- "traefik.tcp.routers.mytcprouter.rule=HostSNI(`myhost.com`)"
traefik.tcp.routers.<router_name>.service

See service for more information.

- "traefik.tcp.routers.mytcprouter.service=myservice"
traefik.tcp.routers.<router_name>.tls

See TLS for more information.

- "traefik.tcp.routers.mytcprouter.tls=true"
traefik.tcp.routers.<router_name>.tls.certresolver

See certResolver for more information.

- "traefik.tcp.routers.mytcprouter.tls.certresolver=myresolver"
traefik.tcp.routers.<router_name>.tls.domains[n].main

See domains for more information.

- "traefik.tcp.routers.mytcprouter.tls.domains[0].main=foobar.com"
traefik.tcp.routers.<router_name>.tls.domains[n].sans

See domains for more information.

- "traefik.tcp.routers.mytcprouter.tls.domains[0].sans=test.foobar.com,dev.foobar.com"
traefik.tcp.routers.<router_name>.tls.options

See options for more information.

- "traefik.tcp.routers.mytcprouter.tls.options=mysoptions"
traefik.tcp.routers.<router_name>.tls.passthrough

See TLS for more information.

- "traefik.tcp.routers.mytcprouter.tls.passthrough=true"

TCP Services

traefik.tcp.services.<service_name>.loadbalancer.server.port

Registers a port of the application.

- "traefik.tcp.services.mytcpservice.loadbalancer.server.port=423"
traefik.tcp.services.<service_name>.loadbalancer.terminationdelay

See termination delay for more information.

- "traefik.tcp.services.mytcpservice.loadbalancer.terminationdelay=100"

Specific Provider Options

traefik.enable

- "traefik.enable=true"

You can tell Traefik to consider (or not) the container by setting traefik.enable to true or false.

This option overrides the value of exposedByDefault.

traefik.docker.network

- "traefik.docker.network=mynetwork"

Overrides the default docker network to use for connections to the container.

If a container is linked to several networks, be sure to set the proper network name (you can check this with docker inspect <container_id>), otherwise it will randomly pick one (depending on how docker is returning them).

Warning

When deploying a stack from a compose file stack, the networks defined are prefixed with stack.

traefik.docker.lbswarm

- "traefik.docker.lbswarm=true"

Enables Swarm's inbuilt load balancer (only relevant in Swarm Mode).

If you enable this option, Traefik will use the virtual IP provided by docker swarm instead of the containers IPs. Which means that Traefik will not perform any kind of load balancing and will delegate this task to swarm.