Traefik & Kubernetes
Path Types on Kubernetes 1.18+
TLS
- Communication Between Traefik and Pods
- Certificates Management
Global Default Backend Ingresses

Traefik & Kubernetes

The Kubernetes Ingress Controller.

Routing Configuration

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

Configuration Example

Configuring Kubernetes Ingress Controller

RBAC

---
kind: ClusterRole
apiVersion: rbac.authorization.k8s.io/v1beta1
metadata:
  name: traefik-ingress-controller
rules:
  - apiGroups:
      - ""
    resources:
      - services
      - endpoints
      - secrets
    verbs:
      - get
      - list
      - watch
  - apiGroups:
      - extensions
      - networking.k8s.io
    resources:
      - ingresses
      - ingressclasses
    verbs:
      - get
      - list
      - watch
  - apiGroups:
      - extensions
    resources:
      - ingresses/status
    verbs:
      - update
---
kind: ClusterRoleBinding
apiVersion: rbac.authorization.k8s.io/v1beta1
metadata:
  name: traefik-ingress-controller
roleRef:
  apiGroup: rbac.authorization.k8s.io
  kind: ClusterRole
  name: traefik-ingress-controller
subjects:
  - kind: ServiceAccount
    name: traefik-ingress-controller
    namespace: default

Ingress

kind: Ingress
apiVersion: networking.k8s.io/v1beta1
metadata:
  name: myingress
  annotations:
    traefik.ingress.kubernetes.io/router.entrypoints: web
spec:
  rules:
    - host: example.com
      http:
        paths:
          - path: /bar
            backend:
              serviceName: whoami
              servicePort: 80
          - path: /foo
            backend:
              serviceName: whoami
              servicePort: 80

Traefik

apiVersion: v1
kind: ServiceAccount
metadata:
  name: traefik-ingress-controller
---
kind: Deployment
apiVersion: apps/v1
metadata:
  name: traefik
  labels:
    app: traefik
spec:
  replicas: 1
  selector:
    matchLabels:
      app: traefik
  template:
    metadata:
      labels:
        app: traefik
    spec:
      serviceAccountName: traefik-ingress-controller
      containers:
        - name: traefik
          image: traefik:v2.3
          args:
            - --log.level=DEBUG
            - --api
            - --api.insecure
            - --entrypoints.web.address=:80
            - --providers.kubernetesingress
          ports:
            - name: web
              containerPort: 80
            - name: admin
              containerPort: 8080
---
apiVersion: v1
kind: Service
metadata:
  name: traefik
spec:
  type: LoadBalancer
  selector:
    app: traefik
  ports:
    - protocol: TCP
      port: 80
      name: web
      targetPort: 80
    - protocol: TCP
      port: 8080
      name: admin
      targetPort: 8080

Whoami

kind: Deployment
apiVersion: apps/v1
metadata:
  name: whoami
  labels:
    app: traefiklabs
    name: whoami
spec:
  replicas: 2
  selector:
    matchLabels:
      app: traefiklabs
      task: whoami
  template:
    metadata:
      labels:
        app: traefiklabs
        task: whoami
    spec:
      containers:
        - name: whoami
          image: traefik/whoami
          ports:
            - containerPort: 80
---
apiVersion: v1
kind: Service
metadata:
  name: whoami
spec:
  ports:
    - name: http
      port: 80
  selector:
    app: traefiklabs
    task: whoami

Annotations

On Ingress

traefik.ingress.kubernetes.io/router.entrypoints

See entry points for more information.

traefik.ingress.kubernetes.io/router.entrypoints: ep1,ep2

traefik.ingress.kubernetes.io/router.middlewares

See middlewares and middlewares overview for more information.

traefik.ingress.kubernetes.io/router.middlewares: auth@file,prefix@kubernetescrd,cb@file

traefik.ingress.kubernetes.io/router.priority

See priority for more information.

traefik.ingress.kubernetes.io/router.priority: "42"

traefik.ingress.kubernetes.io/router.pathmatcher

Overrides the default router rule type used for a path.
Only path-related matcher name can be specified: Path, PathPrefix.

Default PathPrefix

traefik.ingress.kubernetes.io/router.pathmatcher: Path

traefik.ingress.kubernetes.io/router.tls

See tls for more information.

traefik.ingress.kubernetes.io/router.tls: "true"

traefik.ingress.kubernetes.io/router.tls.certresolver

See certResolver for more information.

traefik.ingress.kubernetes.io/router.tls.certresolver: myresolver

traefik.ingress.kubernetes.io/router.tls.domains.n.main

See domains for more information.

traefik.ingress.kubernetes.io/router.tls.domains.0.main: example.org

traefik.ingress.kubernetes.io/router.tls.domains.n.sans

See domains for more information.

traefik.ingress.kubernetes.io/router.tls.domains.0.sans: test.example.org,dev.example.org

traefik.ingress.kubernetes.io/router.tls.options

See options for more information.

traefik.ingress.kubernetes.io/router.tls.options: foobar

On Service

traefik.ingress.kubernetes.io/service.serversscheme

Overrides the default scheme.

traefik.ingress.kubernetes.io/service.serversscheme: h2c

traefik.ingress.kubernetes.io/service.passhostheader

See pass Host header for more information.

traefik.ingress.kubernetes.io/service.passhostheader: "true"

traefik.ingress.kubernetes.io/service.sticky.cookie

See sticky sessions for more information.

traefik.ingress.kubernetes.io/service.sticky.cookie: "true"

traefik.ingress.kubernetes.io/service.sticky.cookie.name

See sticky sessions for more information.

traefik.ingress.kubernetes.io/service.sticky.cookie.name: foobar

traefik.ingress.kubernetes.io/service.sticky.cookie.secure

See sticky sessions for more information.

traefik.ingress.kubernetes.io/service.sticky.cookie.secure: "true"

traefik.ingress.kubernetes.io/service.sticky.cookie.samesite

See sticky sessions for more information.

traefik.ingress.kubernetes.io/service.sticky.cookie.samesite: "none"

traefik.ingress.kubernetes.io/service.sticky.cookie.httponly

See sticky sessions for more information.

traefik.ingress.kubernetes.io/service.sticky.cookie.httponly: "true"

Path Types on Kubernetes 1.18+

If the Kubernetes cluster version is 1.18+, the new pathType property can be leveraged to define the rules matchers:

Exact: This path type forces the rule matcher to Path
Prefix: This path type forces the rule matcher to PathPrefix

Please see this documentation for more information.

Multiple Matches

In the case of multiple matches, Traefik will not ensure the priority of a Path matcher over a PathPrefix matcher, as stated in this documentation.

TLS

Communication Between Traefik and Pods

Traefik automatically requests endpoint information based on the service provided in the ingress spec. Although Traefik will connect directly to the endpoints (pods), it still checks the service port to see if TLS communication is required.

There are 3 ways to configure Traefik to use https to communicate with pods:

If the service port defined in the ingress spec is 443 (note that you can still use targetPort to use a different port on your pod).
If the service port defined in the ingress spec has a name that starts with https (such as https-api, https-web or just https).
If the ingress spec includes the annotation traefik.ingress.kubernetes.io/service.serversscheme: https.

If either of those configuration options exist, then the backend communication protocol is assumed to be TLS, and will connect via TLS automatically.

Info

Please note that by enabling TLS communication between traefik and your pods, you will have to have trusted certificates that have the proper trust chain and IP subject name. If this is not an option, you may need to skip TLS certificate verification. See the insecureSkipVerify setting for more details.

Certificates Management

Using a secret

Ingress

kind: Ingress
apiVersion: networking.k8s.io/v1beta1
metadata:
  name: foo
  namespace: production
spec:
  rules:
  - host: example.net
    http:
      paths:
      - path: /bar
        backend:
          serviceName: service1
          servicePort: 80
  tls:
  - secretName: supersecret

Secret

apiVersion: v1
kind: Secret
metadata:
  name: supersecret
data:
  tls.crt: LS0tLS1CRUdJTiBDRVJUSUZJQ0FURS0tLS0tCi0tLS0tRU5EIENFUlRJRklDQVRFLS0tLS0=
  tls.key: LS0tLS1CRUdJTiBQUklWQVRFIEtFWS0tLS0tCi0tLS0tRU5EIFBSSVZBVEUgS0VZLS0tLS0=

TLS certificates can be managed in Secrets objects.

Info

Only TLS certificates provided by users can be stored in Kubernetes Secrets. Let’s Encrypt certificates cannot be managed in Kubernetes Secrets yet.

Global Default Backend Ingresses

Ingresses can be created that look like the following:

apiVersion: networking.k8s.io/v1beta1
kind: Ingress
metadata:
 name: cheese
spec:
 backend:
   serviceName: stilton
   servicePort: 80

This ingress follows the Global Default Backend property of ingresses. This will allow users to create a “default router” that will match all unmatched requests.

Info

Due to Traefik’s use of priorities, you may have to set this ingress priority lower than other ingresses in your environment, to avoid this global ingress from satisfying requests that could match other ingresses.

To do this, use the traefik.ingress.kubernetes.io/router.priority annotation (as seen in Annotations on Ingress) on your ingresses accordingly.