Traefik & Kubernetes

The Kubernetes Ingress Controller.

The Traefik Kubernetes Ingress provider is a Kubernetes Ingress controller; that is to say, it manages access to cluster services by supporting the Ingress specification.

Requirements

Traefik supports 1.14+ Kubernetes clusters.

Routing Configuration

See the dedicated section in routing.

Enabling and Using the Provider

You can enable the provider in the static configuration:

File (YAML)

  1. providers:
  2.   kubernetesIngress: {}

File (TOML)

  1. [providers.kubernetesIngress]

CLI

  1. --providers.kubernetesingress=true

The provider then watches for incoming ingresses events, such as the example below, and derives the corresponding dynamic configuration from it, which in turn creates the resulting routers, services, handlers, etc.

Ingress

  1. apiVersion: networking.k8s.io/v1
  2. kind: Ingress
  3. metadata:
  4.   name: foo
  5.   namespace: production
  7. spec:
  8.   rules:
  9.     - host: example.net
  10.       http:
  11.         paths:
  12.           - path: /bar
  13.             pathType: Exact
  14.             backend:
  15.               service:
  16.                 name:  service1
  17.                 port:
  18.                   number: 80
  19.           - path: /foo
  20.             pathType: Exact
  21.             backend:
  22.               service:
  23.                 name:  service1
  24.                 port:
  25.                   number: 80

Ingress v1beta1 (deprecated)

  1. apiVersion: networking.k8s.io/v1beta1
  2. kind: Ingress
  3. metadata:
  4.   name: foo
  5.   namespace: production
  7. spec:
  8.   rules:
  9.     - host: example.net
  10.       http:
  11.         paths:
  12.           - path: /bar
  13.             backend:
  14.               serviceName: service1
  15.               servicePort: 80
  16.           - path: /foo
  17.             backend:
  18.               serviceName: service1
  19.               servicePort: 80

LetsEncrypt Support with the Ingress Provider

By design, Traefik is a stateless application, meaning that it only derives its configuration from the environment it runs in, without additional configuration. For this reason, users can run multiple instances of Traefik at the same time to achieve HA, as is a common pattern in the kubernetes ecosystem.

When using a single instance of Traefik Proxy with Let’s Encrypt, you should encounter no issues. However, this could be a single point of failure. Unfortunately, it is not possible to run multiple instances of Traefik 2.0 with Let’s Encrypt enabled, because there is no way to ensure that the correct instance of Traefik receives the challenge request, and subsequent responses. Previous versions of Traefik used a KV store to attempt to achieve this, but due to sub-optimal performance that feature was dropped in 2.0.

If you need Let’s Encrypt with high availability in a Kubernetes environment, we recommend using Traefik Enterprise which includes distributed Let’s Encrypt as a supported feature.

If you want to keep using Traefik Proxy, LetsEncrypt HA can be achieved by using a Certificate Controller such as Cert-Manager. When using Cert-Manager to manage certificates, it creates secrets in your namespaces that can be referenced as TLS secrets in your ingress objects.

Provider Configuration

endpoint

Optional, Default=””

The Kubernetes server endpoint URL.

When deployed into Kubernetes, Traefik reads the environment variables KUBERNETES_SERVICE_HOST and KUBERNETES_SERVICE_PORT or KUBECONFIG to construct the endpoint.

The access token is looked up in /var/run/secrets/kubernetes.io/serviceaccount/token and the SSL CA certificate in /var/run/secrets/kubernetes.io/serviceaccount/ca.crt. Both are mounted automatically when deployed inside Kubernetes.

The endpoint may be specified to override the environment variable values inside a cluster.

When the environment variables are not found, Traefik tries to connect to the Kubernetes API server with an external-cluster client. In this case, the endpoint is required. Specifically, it may be set to the URL used by kubectl proxy to connect to a Kubernetes cluster using the granted authentication and authorization of the associated kubeconfig.

File (YAML)

  1. providers:
  2.   kubernetesIngress:
  3.     endpoint: "http://localhost:8080"
  4.     # ...

File (TOML)

  1. [providers.kubernetesIngress]
  2.   endpoint = "http://localhost:8080"
  3.   # ...

CLI

  1. --providers.kubernetesingress.endpoint=http://localhost:8080

token

Optional, Default=””

Bearer token used for the Kubernetes client configuration.

File (YAML)

  1. providers:
  2.   kubernetesIngress:
  3.     token: "mytoken"
  4.     # ...

File (TOML)

  1. [providers.kubernetesIngress]
  2.   token = "mytoken"
  3.   # ...

CLI

  1. --providers.kubernetesingress.token=mytoken

certAuthFilePath

Optional, Default=””

Path to the certificate authority file. Used for the Kubernetes client configuration.

File (YAML)

  1. providers:
  2.   kubernetesIngress:
  3.     certAuthFilePath: "/my/ca.crt"
  4.     # ...

File (TOML)

  1. [providers.kubernetesIngress]
  2.   certAuthFilePath = "/my/ca.crt"
  3.   # ...

CLI

  1. --providers.kubernetesingress.certauthfilepath=/my/ca.crt

namespaces

Optional, Default: []

Array of namespaces to watch. If left empty, watches all namespaces if the value of namespaces.

File (YAML)

  1. providers:
  2.   kubernetesIngress:
  3.     namespaces:
  4.       - "default"
  5.       - "production"
  6.     # ...

File (TOML)

  1. [providers.kubernetesIngress]
  2.   namespaces = ["default", "production"]
  3.   # ...

CLI

  1. --providers.kubernetesingress.namespaces=default,production

labelSelector

Optional, Default: “”

A label selector can be defined to filter on specific Ingress objects only. If left empty, Traefik processes all Ingress objects in the configured namespaces.

See label-selectors for details.

File (YAML)

  1. providers:
  2.   kubernetesIngress:
  3.     labelSelector: "app=traefik"
  4.     # ...

File (TOML)

  1. [providers.kubernetesIngress]
  2.   labelSelector = "app=traefik"
  3.   # ...

CLI

  1. --providers.kubernetesingress.labelselector="app=traefik"

ingressClass

Optional, Default: “”

Value of kubernetes.io/ingress.class annotation that identifies Ingress objects to be processed.

If the parameter is set, only Ingresses containing an annotation with the same value are processed. Otherwise, Ingresses missing the annotation, having an empty value, or the value traefik are processed.

Kubernetes 1.18+

If the Kubernetes cluster version is 1.18+, the new IngressClass resource can be leveraged to identify Ingress objects that should be processed. In that case, Traefik will look for an IngressClass in the cluster with the controller value equal to traefik.io/ingress-controller.

In addition to the controller value matching mechanism, the property ingressClass (if set) will be used to select IngressClasses by applying a strict matching on their name.

Please see this article for more information or the example below.

IngressClass

  1. apiVersion: networking.k8s.io/v1beta1
  2. kind: IngressClass
  3. metadata:
  4.   name: traefik-lb
  5. spec:
  6.   controller: traefik.io/ingress-controller

Ingress

  1. apiVersion: networking.k8s.io/v1beta1
  2. kind: Ingress
  3. metadata:
  4.   name: example-ingress
  5. spec:
  6.   ingressClassName: traefik-lb
  7.   rules:
  8.   - host: "*.example.com"
  9.     http:
  10.       paths:
  11.       - path: /example
  12.         backend:
  13.           serviceName: example-service
  14.           servicePort: 80

Kubernetes 1.19+

If the Kubernetes cluster version is 1.19+, prefer using the networking.k8s.io/v1 apiVersion of Ingress and IngressClass.

IngressClass

  1. apiVersion: networking.k8s.io/v1
  2. kind: IngressClass
  3. metadata:
  4.   name: traefik-lb
  5. spec:
  6.   controller: traefik.io/ingress-controller

Ingress

  1. apiVersion: networking.k8s.io/v1
  2. kind: Ingress
  3. metadata:
  4.   name: example-ingress
  5. spec:
  6.   ingressClassName: traefik-lb
  7.   rules:
  8.   - host: "*.example.com"
  9.     http:
  10.       paths:
  11.       - path: /example
  12.         pathType: Exact
  13.         backend:
  14.           service:
  15.             name: example-service
  16.             port:
  17.                 number: 80

File (YAML)

  1. providers:
  2.   kubernetesIngress:
  3.     ingressClass: "traefik-internal"
  4.     # ...

File (TOML)

  1. [providers.kubernetesIngress]
  2.   ingressClass = "traefik-internal"
  3.   # ...

CLI

  1. --providers.kubernetesingress.ingressclass=traefik-internal

ingressEndpoint

hostname

Optional, Default: “”

Hostname used for Kubernetes Ingress endpoints.

File (YAML)

  1. providers:
  2.   kubernetesIngress:
  3.     ingressEndpoint:
  4.       hostname: "example.net"
  5.     # ...

File (TOML)

  1. [providers.kubernetesIngress.ingressEndpoint]
  2.   hostname = "example.net"
  3.   # ...

CLI

  1. --providers.kubernetesingress.ingressendpoint.hostname=example.net

ip

Optional, Default: “”

IP used for Kubernetes Ingress endpoints.

File (YAML)

  1. providers:
  2.   kubernetesIngress:
  3.     ingressEndpoint:
  4.       ip: "1.2.3.4"
  5.     # ...

File (TOML)

  1. [providers.kubernetesIngress.ingressEndpoint]
  2.   ip = "1.2.3.4"
  3.   # ...

CLI

  1. --providers.kubernetesingress.ingressendpoint.ip=1.2.3.4

publishedService

Optional, Default: “”

Published Kubernetes Service to copy status from. Format: namespace/servicename.

File (YAML)

  1. providers:
  2.   kubernetesIngress:
  3.     ingressEndpoint:
  4.       publishedService: "namespace/foo-service"
  5.     # ...

File (TOML)

  1. [providers.kubernetesIngress.ingressEndpoint]
  2.   publishedService = "namespace/foo-service"
  3.   # ...

CLI

  1. --providers.kubernetesingress.ingressendpoint.publishedservice=namespace/foo-service

throttleDuration

Optional, Default: 0

The throttleDuration option defines how often the provider is allowed to handle events from Kubernetes. This prevents a Kubernetes cluster that updates many times per second from continuously changing your Traefik configuration.

If left empty, the provider does not apply any throttling and does not drop any Kubernetes events.

The value of throttleDuration should be provided in seconds or as a valid duration format, see time.ParseDuration.

File (YAML)

  1. providers:
  2.   kubernetesIngress:
  3.     throttleDuration: "10s"
  4.     # ...

File (TOML)

  1. [providers.kubernetesIngress]
  2.   throttleDuration = "10s"
  3.   # ...

CLI

  1. --providers.kubernetesingress.throttleDuration=10s

allowEmptyServices

_Optional, Default: false

File (YAML)

  1. providers:
  2.   kubernetesIngress:
  3.     allowEmptyServices: true
  4.     # ...

File (TOML)

  1. [providers.kubernetesIngress]
  2.   allowEmptyServices = true
  3.   # ...

CLI

  1. --providers.kubernetesingress.allowEmptyServices=true

Allow the creation of services if there are no endpoints available. This results in 503 http responses instead of 404.

allowExternalNameServices

Optional, Default: false

If the parameter is set to true, Ingresses are able to reference ExternalName services.

File (YAML)

  1. providers:
  2.   kubernetesIngress:
  3.     allowExternalNameServices: true
  4.     # ...

File (TOML)

  1. [providers.kubernetesIngress]
  2.   allowExternalNameServices = true
  3.   # ...

CLI

  1. --providers.kubernetesingress.allowexternalnameservices=true

Further

To learn more about the various aspects of the Ingress specification that Traefik supports, many examples of Ingresses definitions are located in the test examples of the Traefik repository.