Traefik Proxy Source

• Traefik Documentation
• Traefik Helm Chart

This tutorial describes how to configure ExternalDNS to use the Traefik Proxy source.
It is meant to supplement the other provider-specific setup tutorials.

Manifest (for clusters without RBAC enabled)

apiVersion: apps/v1
kind: Deployment
metadata:
  name: external-dns
spec:
  strategy:
    type: Recreate
  selector:
    matchLabels:
      app: external-dns
  template:
    metadata:
      labels:
        app: external-dns
    spec:
      containers:
      - name: external-dns
        # update this to the desired external-dns version
        image: registry.k8s.io/external-dns/external-dns:v0.17.0
        args:
        - --source=traefik-proxy
        - --provider=aws
        - --registry=txt
        - --txt-owner-id=my-identifier

Manifest (for clusters with RBAC enabled)

---
apiVersion: v1
kind: ServiceAccount
metadata:
  name: external-dns
---
apiVersion: rbac.authorization.k8s.io/v1
kind: ClusterRole
metadata:
  name: external-dns
rules:
- apiGroups: [""]
  resources: ["services","pods"]
  verbs: ["get","watch","list"]
- apiGroups: ["discovery.k8s.io"]
  resources: ["endpointslices"]
  verbs: ["get","watch","list"]
- apiGroups: [""]
  resources: ["nodes"]
  verbs: ["list","watch"]
- apiGroups: ["traefik.containo.us","traefik.io"]
  resources: ["ingressroutes", "ingressroutetcps", "ingressrouteudps"]
  verbs: ["get","watch","list"]
---
apiVersion: rbac.authorization.k8s.io/v1
kind: ClusterRoleBinding
metadata:
  name: external-dns-viewer
roleRef:
  apiGroup: rbac.authorization.k8s.io
  kind: ClusterRole
  name: external-dns
subjects:
- kind: ServiceAccount
  name: external-dns
  namespace: default
---
apiVersion: apps/v1
kind: Deployment
metadata:
  name: external-dns
spec:
  strategy:
    type: Recreate
  selector:
    matchLabels:
      app: external-dns
  template:
    metadata:
      labels:
        app: external-dns
    spec:
      serviceAccountName: external-dns
      containers:
      - name: external-dns
        # update this to the desired external-dns version
        image: registry.k8s.io/external-dns/external-dns:v0.17.0
        args:
        - --source=traefik-proxy
        - --provider=aws
        - --registry=txt
        - --txt-owner-id=my-identifier

Deploying a Traefik IngressRoute

Create an IngressRoute file called ‘ingress-route-default’ with the following contents:

apiVersion: traefik.io/v1alpha1
kind: IngressRoute
metadata:
  name: traefik-ingress
  annotations:
    external-dns.alpha.kubernetes.io/target: traefik.example.com
    kubernetes.io/ingress.class: traefik
spec:
  entryPoints:
    - web
    - websecure
  routes:
    - match: Host(`application.example.com`)
      kind: Rule
      services:
        - name: service
          namespace: namespace
          port: port

Note the annotation on the IngressRoute (external-dns.alpha.kubernetes.io/target); use the same hostname as the traefik DNS.

ExternalDNS uses this annotation to determine what services should be registered with DNS.

Create the IngressRoute:

kubectl create -f docs/snippets/traefik-proxy/ingress-route-default.yaml

Depending where you run your IngressRoute it can take a little while for ExternalDNS synchronize the DNS record.

Support private and public routing

To create a more robust and manageable Kubernetes environment, leverage separate Ingress classes to finely control public and private routing’s security, performance, and operational policies. Similar approach could work in multi-tenant environments.

For this we are going to need two instances of traefik (public and private) as well as two instances of external-dns.

The traefik configuration should contain (for more detailed configured validate with the vendor)

---
type: public
providers:
  kubernetesCRD:
    ingressClass: traefik-public

  kubernetesIngress:
    ingressClass: traefik-public
---
type: private
providers:
  kubernetesCRD:
    ingressClass: traefik-private

  kubernetesIngress:
    ingressClass: traefik-private

Create a IngressRoutes files with the following contents:

---
apiVersion: traefik.io/v1
kind: IngressRoute
metadata:
  name: traefik-public-abc
  annotations:
    kubernetes.io/ingress.class: traefik-public
spec:
  entryPoints:
    - web
    - websecure
  routes:
    - match: Host(`application.public.example.com`)
      kind: Rule
      services:
        - name: service
          namespace: namespace
          port: port
  tls:
    secretName: traefik-tls-cert-public
---
apiVersion: traefik.io/v1
kind: IngressRoute
metadata:
  name: traefik-private-abc
  annotations:
    kubernetes.io/ingress.class: traefik-private
spec:
  entryPoints:
    - web
    - websecure
  routes:
    - match: Host(`application.private.tlc`)
      kind: Rule
      services:
        - name: service
          namespace: namespace
          port: port
  tls:
    secretName: traefik-tls-cert-private

And the arguments for external-dns instances should looks like

---
args:
  - --source=traefik-proxy
  - --annotation-filter="kubernetes.io/ingress.class=traefik-public"
---
args:
  - --source=traefik-proxy
  - --annotation-filter="kubernetes.io/ingress.class=traefik-private"

Cleanup

Now that we have verified that ExternalDNS will automatically manage Traefik DNS records, we can delete the tutorial’s example:

kubectl delete -f docs/snippets/traefik-proxy/ingress-route-default.yaml
kubectl delete -f externaldns.yaml

Additional Flags

Flag	Description
–traefik-disable-legacy	Disable listeners on Resources under traefik.containo.us
–traefik-disable-new	Disable listeners on Resources under traefik.io

Disabling Resource Listeners

Traefik has deprecated the legacy API group, traefik.containo.us, in favor of traefik.io. By default the traefik-proxy source will listen for resources under both API groups; however, this may cause timeouts with the following message

FATA[0060] failed to sync traefik.io/v1alpha1, Resource=ingressroutes: context deadline exceeded

In this case you can disable one or the other API groups with --traefik-disable-new or --traefik-disable-legacy