# Traefik & Rancher

A Story of Labels, Services & Container
{: .subtitle }

![Rancher](../assets/img/providers/rancher.png)

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

## Configuration Examples

??? example "Configuring Rancher & Deploying / Exposing Services"

    Enabling the rancher provider

    ```toml
    [provider.rancher]
    ```

    Attaching labels to services

    ```yaml
    labels:
      - traefik.http.services.my-service.rule=Host(my-domain)
    ```

## Provider Configuration Options

!!! tip "Browse the Reference"
    If you're in a hurry, maybe you'd rather go through the configuration reference:
    
    ```toml
    ################################################################
    # Rancher Provider
    ################################################################
    
    # Enable Rancher Provider.
    [rancher]
    
    # Expose Rancher services by default in Traefik.
    #
    # Optional
    #
    ExposedByDefault = "true"
    
    # Enable watch Rancher changes.
    #
    # Optional
    #
    watch = true
    
    # Filter services with unhealthy states and inactive states.
    #
    # Optional
    #
    EnableServiceHealthFilter = true
    
    # Defines the polling interval (in seconds).
    #
    # Optional
    #
    RefreshSeconds = true
    
    # Poll the Rancher metadata service for changes every `rancher.refreshSeconds`, which is less accurate
    #
    # Optional
    #
    IntervalPoll = false
    
    # Prefix used for accessing the Rancher metadata service
    #
    # Optional
    #
    Prefix = 15
    ```

### `ExposedByDefault`

_Optional, Default=true_

Expose Rancher services by default in Traefik.
If set to false, services that don't have a `traefik.enable=true` label will be ignored from the resulting routing configuration.

### `DefaultRule`

_Optional, Default=Host(`{{ normalize .Name }}`)_

The default host rule for all services.

For a given container if no routing rule was defined by a label, it is defined by this defaultRule instead.
It must be a valid [Go template](https://golang.org/pkg/text/template/),
augmented with the [sprig template functions](http://masterminds.github.io/sprig/).
The service name can be accessed as the `Name` identifier,
and the template has access to all the labels defined on this container.

```toml
defaultRule = "Host(`{{ .Name }}.{{ index .Labels \"customLabel\"}}`)"
```

This option can be overridden on a container basis with the `traefik.http.routers.Router1.rule` label.

### `EnableServiceHealthFilter`

_Optional, Default=true_

Filter services with unhealthy states and inactive states.

### `RefreshSeconds`

_Optional, Default=15_

Defines the polling interval (in seconds).

### `IntervalPoll`

_Optional, Default=false_

Poll the Rancher metadata service for changes every `rancher.refreshSeconds`,
which is less accurate than the default long polling technique which will provide near instantaneous updates to Traefik.

### `Prefix`

_Optional, Default=/latest_

Prefix used for accessing the Rancher metadata service

### General

Traefik creates, for each rancher service, a corresponding [service](../routing/services/index.md) and [router](../routing/routers/index.md).

The Service automatically gets a server per container in this rancher service, and the router gets a default rule attached to it, based on the service name.

### Routers

To update the configuration of the Router automatically attached to the container, add labels starting with `traefik.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(my-domain)`.

Every [Router](../routing/routers/index.md) parameter can be updated this way.

### 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 load balancer method,
you'd add the label `traefik.http.services.{name-of-your-choice}.loadbalancer.method=drr`.

Every [Service](../routing/services/index.md) parameter can be updated this way.

### 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 [`schemeredirect`](../middlewares/redirectscheme.md) named `my-redirect`, you'd write `traefik.http.middlewares.my-redirect.schemeredirect.scheme: https`.

??? example "Declaring and Referencing a Middleware"
    
    ```yaml
    # ...
    labels:
     - traefik.http.middlewares.my-redirect.schemeredirect.scheme=https
     - traefik.http.routers.middlewares=my-redirect
    ```

!!! warning "Conflicts in Declaration"

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

### Specific Options

#### `traefik.enable`

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.tags`

Sets the tags for [constraints filtering](./overview.md#constraints-configuration).

#### Port Lookup

Traefik is now capable of detecting the port to use, by following the default rancher flow.
That means, if you just expose lets say port :1337 on the rancher ui, traefik will pick up this port and use it.