Install the Traefik Ingress Controller on k0s#

You can configure k0s with the Traefik ingress controller, a MetalLB service loadbalancer, and deploy the Traefik Dashboard using a service sample. To do this you leverage Helm's extensible bootstrapping functionality to add the correct extensions to the k0s.yaml file during cluster configuration.

1. Configure k0s.yaml#

Configure k0s to install Traefik and MetalLB during cluster bootstrapping by adding their Helm charts as extensions in the k0s configuration file (k0s.yaml).

Note:

A good practice is to have a small range of IP addresses that are addressable on your network, preferably outside the assignment pool your DHCP server allocates (though any valid IP range should work locally on your machine). Providing an addressable range allows you to access your load balancer and Ingress services from anywhere on your local network.

extensions:
  helm:
    repositories:
    - name: traefik
      url: https://helm.traefik.io/traefik
    - name: bitnami
      url: https://charts.bitnami.com/bitnami
    charts:
    - name: traefik
      chartname: traefik/traefik
      version: "9.11.0"
      namespace: default
    - name: metallb
      chartname: bitnami/metallb
      version: "1.0.1"
      namespace: default
      values: |2
        configInline:
          address-pools:
          - name: generic-cluster-pool
            protocol: layer2
            addresses:
            - 192.168.0.5-192.168.0.10

2. Retrieve the Load Balancer IP#

After you start your cluster, run kubectl get all to confirm the deployment of Traefik and MetalLB. The command should return a response with the metallb and traefik resources, along with a service load balancer that has an assigned EXTERNAL-IP.

kubectl get all

Output:

NAME                                                 READY   STATUS    RESTARTS   AGE
pod/metallb-1607085578-controller-864c9757f6-bpx6r   1/1     Running   0          81s
pod/metallb-1607085578-speaker-245c2                 1/1     Running   0          60s
pod/traefik-1607085579-77bbc57699-b2f2t              1/1     Running   0          81s

NAME                         TYPE           CLUSTER-IP       EXTERNAL-IP      PORT(S)                      AGE
service/kubernetes           ClusterIP      10.96.0.1        <none>           443/TCP                      96s
service/traefik-1607085579   LoadBalancer   10.105.119.102   192.168.0.5      80:32153/TCP,443:30791/TCP   84s

NAME                                        DESIRED   CURRENT   READY   UP-TO-DATE   AVAILABLE   NODE SELECTOR            AGE
daemonset.apps/metallb-1607085578-speaker   1         1         1       1            1           kubernetes.io/os=linux   87s

NAME                                            READY   UP-TO-DATE   AVAILABLE   AGE
deployment.apps/metallb-1607085578-controller   1/1     1            1           87s
deployment.apps/traefik-1607085579              1/1     1            1           84s

NAME                                                       DESIRED   CURRENT   READY   AGE
replicaset.apps/metallb-1607085578-controller-864c9757f6   1         1         1       81s
replicaset.apps/traefik-1607085579-77bbc57699              1         1         1       81s

Take note of the EXTERNAL-IP given to the service/traefik-n load balancer. In this example, 192.168.0.5 has been assigned and can be used to access services via the Ingress proxy:

NAME                         TYPE           CLUSTER-IP       EXTERNAL-IP      PORT(S)                      AGE
service/traefik-1607085579   LoadBalancer   10.105.119.102   192.168.0.5      80:32153/TCP,443:30791/TCP   84s

Receiving a 404 response here is normal, as you've not configured any Ingress resources to respond yet:

$ curl http://192.168.0.5
404 page not found

3. Deploy and access the Traefik Dashboard#

With an available and addressable load balancer present on your cluster, now you can quickly deploy the Traefik dashboard and access it from anywhere on your LAN (assuming that MetalLB is configured with an addressable range).

Create the Traefik Dashboard IngressRoute in a YAML file:

apiVersion: traefik.containo.us/v1alpha1
kind: IngressRoute
metadata:
  name: dashboard
spec:
  entryPoints:
    - web
  routes:
    - match: PathPrefix(`/dashboard`) || PathPrefix(`/api`)
      kind: Rule
      services:
        - name: api@internal
          kind: TraefikService

Deploy the resource:
```
root@k0s-host ➜ kubectl apply -f traefik-dashboard.yaml
```
Output:
```
ingressroute.traefik.containo.us/dashboard created
```
At this point you should be able to access the dashboard using the EXTERNAL-IP that you noted above by visiting http://192.168.0.5 in your browser:

Create a simple whoami Deployment, Service, and Ingress manifest:

apiVersion: apps/v1
kind: Deployment
metadata:
  name: whoami-deployment
spec:
  replicas: 1
  selector:
    matchLabels:
      app: whoami
  template:
    metadata:
      labels:
        app: whoami
    spec:
      containers:
      - name: whoami-container
        image: containous/whoami
---
apiVersion: v1
kind: Service
metadata:
  name: whoami-service
spec:
  ports:
  - name: http
    targetPort: 80
    port: 80
  selector:
    app: whoami
---
apiVersion: networking.k8s.io/v1
kind: Ingress
metadata:
  name: whoami-ingress
spec:
  rules:
  - http:
      paths:
      - path: /whoami
        pathType: Exact
        backend:
          service:
            name: whoami-service
            port:
              number: 80

Apply the manifests:

root@k0s-host ➜ kubectl apply -f whoami.yaml

Output:

deployment.apps/whoami-deployment created
service/whoami-service created
ingress.networking.k8s.io/whoami-ingress created

Test the ingress and service:

curl http://192.168.0.5/whoami

Output:

Hostname: whoami-deployment-85bfbd48f-7l77c
IP: 127.0.0.1
IP: ::1
IP: 10.244.214.198
IP: fe80::b049:f8ff:fe77:3e64
RemoteAddr: 10.244.214.196:34858
GET /whoami HTTP/1.1
Host: 192.168.0.5
User-Agent: curl/7.68.0
Accept: */*
Accept-Encoding: gzip
X-Forwarded-For: 192.168.0.82
X-Forwarded-Host: 192.168.0.5
X-Forwarded-Port: 80
X-Forwarded-Proto: http
X-Forwarded-Server: traefik-1607085579-77bbc57699-b2f2t
X-Real-Ip: 192.168.0.82

Further details#

With the Traefik Ingress Controller it is possible to use 3rd party tools, such as ngrok, to go further and expose your load balancer to the world. In doing this you enable dynamic certificate provisioning through Let's Encrypt, using either cert-manager or Traefik's own built-in ACME provider.