# Kubernetes Ingress Controller This guide explains how to use Træfɪk as an Ingress controller in a Kubernetes cluster. If you are not familiar with Ingresses in Kubernetes you might want to read the [Kubernetes user guide](http://kubernetes.io/docs/user-guide/ingress/) The config files used in this guide can be found in the [examples directory](https://github.com/containous/traefik/tree/master/examples/k8s) ## Prerequisites 1. A working Kubernetes cluster. If you want to follow along with this guide, you should setup [minikube](http://kubernetes.io/docs/getting-started-guides/minikube/) on your machine, as it is the quickest way to get a local Kubernetes cluster setup for experimentation and development. 2. The `kubectl` binary should be [installed on your workstation](http://kubernetes.io/docs/getting-started-guides/minikube/#download-kubectl). ## Deploy Træfɪk We are going to deploy Træfɪk with a [Deployment](http://kubernetes.io/docs/user-guide/deployments/), as this will allow you to easily roll out config changes or update the image. ```yaml kind: Deployment apiVersion: extensions/v1beta1 metadata: name: traefik-ingress-controller namespace: kube-system labels: k8s-app: traefik-ingress-lb spec: replicas: 1 selector: matchLabels: k8s-app: traefik-ingress-lb template: metadata: labels: k8s-app: traefik-ingress-lb name: traefik-ingress-lb spec: terminationGracePeriodSeconds: 60 containers: - image: traefik name: traefik-ingress-lb resources: limits: cpu: 200m memory: 30Mi requests: cpu: 100m memory: 20Mi ports: - containerPort: 80 hostPort: 80 - containerPort: 8080 args: - --web - --kubernetes ``` [examples/k8s/traefik.yaml](https://github.com/containous/traefik/tree/master/examples/k8s/traefik.yaml) > notice that we binding port 80 on the Træfɪk container to port 80 on the host. > With a multi node cluster we might expose Træfɪk with a NodePort or LoadBalancer service > and run more than 1 replica of Træfɪk for high availability. To deploy Træfɪk to your cluster start by submitting the deployment to the cluster with `kubectl`: ```sh kubectl apply -f examples/k8s/traefik.yaml ``` ### Check the deployment Now lets check if our deployment was successful. Start by listing the pods in the `kube-system` namespace: ```sh $kubectl --namespace=kube-system get pods NAME READY STATUS RESTARTS AGE kube-addon-manager-minikubevm 1/1 Running 0 4h kubernetes-dashboard-s8krj 1/1 Running 0 4h traefik-ingress-controller-678226159-eqseo 1/1 Running 0 7m ``` You should see that after submitting the Deployment to Kubernetes it has launched a pod, and it is now running. _It might take a few moments for kubernetes to pull the Træfɪk image and start the container._ > You could also check the deployment with the Kubernetes dashboard, run > `minikube dashboard` to open it in your browser, then choose the `kube-system` > namespace from the menu at the top right of the screen. You should now be able to access Træfɪk on port 80 of your minikube instance. ```sh curl $(minikube ip) 404 page not found ``` > We expect to see a 404 response here as we haven't yet given Træfɪk any configuration. ## Submitting An Ingress to the cluster. Lets start by creating a Service and an Ingress that will expose the [Træfɪk Web UI](https://github.com/containous/traefik#web-ui). ```yaml apiVersion: v1 kind: Service metadata: name: traefik-web-ui namespace: kube-system spec: selector: k8s-app: traefik-ingress-lb ports: - port: 80 targetPort: 8080 --- apiVersion: extensions/v1beta1 kind: Ingress metadata: name: traefik-web-ui namespace: kube-system spec: rules: - host: traefik-ui.local http: paths: - backend: serviceName: traefik-web-ui servicePort: 80 ``` [examples/k8s/ui.yaml](https://github.com/containous/traefik/tree/master/examples/k8s/ui.yaml) ```sh kubectl apply -f examples/k8s/ui.yaml ``` Now lets setup an entry in our /etc/hosts file to route `traefik-ui.local` to our cluster. > In production you would want to set up real dns entries. > You can get the ip address of your minikube instance by running `minikube ip` ``` echo "$(minikube ip) traefik-ui.local" | sudo tee -a /etc/hosts ``` We should now be able to visit [traefik-ui.local](http://traefik-ui.local) in the browser and view the Træfɪk Web UI. ## Name based routing In this example we are going to setup websites for 3 of the United Kingdoms best loved cheeses, Cheddar, Stilton and Wensleydale. First lets start by launching the 3 pods for the cheese websites. ```yaml --- kind: Deployment apiVersion: extensions/v1beta1 metadata: name: stilton labels: app: cheese cheese: stilton spec: replicas: 2 selector: matchLabels: app: cheese task: stilton template: metadata: labels: app: cheese task: stilton version: v0.0.1 spec: containers: - name: cheese image: errm/cheese:stilton resources: requests: cpu: 100m memory: 50Mi limits: cpu: 100m memory: 50Mi ports: - containerPort: 80 --- kind: Deployment apiVersion: extensions/v1beta1 metadata: name: cheddar labels: app: cheese cheese: cheddar spec: replicas: 2 selector: matchLabels: app: cheese task: cheddar template: metadata: labels: app: cheese task: cheddar version: v0.0.1 spec: containers: - name: cheese image: errm/cheese:cheddar resources: requests: cpu: 100m memory: 50Mi limits: cpu: 100m memory: 50Mi ports: - containerPort: 80 --- kind: Deployment apiVersion: extensions/v1beta1 metadata: name: wensleydale labels: app: cheese cheese: wensleydale spec: replicas: 2 selector: matchLabels: app: cheese task: wensleydale template: metadata: labels: app: cheese task: wensleydale version: v0.0.1 spec: containers: - name: cheese image: errm/cheese:wensleydale resources: requests: cpu: 100m memory: 50Mi limits: cpu: 100m memory: 50Mi ports: - containerPort: 80 ``` [examples/k8s/cheese-deployments.yaml](https://github.com/containous/traefik/tree/master/examples/k8s/cheese-deployments.yaml) ```sh kubectl apply -f examples/k8s/cheese-deployments.yaml ``` Next we need to setup a service for each of the cheese pods. ```yaml --- apiVersion: v1 kind: Service metadata: name: stilton spec: ports: - name: http targetPort: 80 port: 80 selector: app: cheese task: stilton --- apiVersion: v1 kind: Service metadata: name: cheddar spec: ports: - name: http targetPort: 80 port: 80 selector: app: cheese task: cheddar --- apiVersion: v1 kind: Service metadata: name: wensleydale annotations: traefik.backend.circuitbreaker: "NetworkErrorRatio() > 0.5" spec: ports: - name: http targetPort: 80 port: 80 selector: app: cheese task: wensleydale ``` > Notice that we also set a [circuit breaker expression](https://docs.traefik.io/basics/#backends) for one of the backends > by setting the `traefik.backend.circuitbreaker` annotation on the service. [examples/k8s/cheese-services.yaml](https://github.com/containous/traefik/tree/master/examples/k8s/cheese-services.yaml) ```sh kubectl apply -f examples/k8s/cheese-services.yaml ``` Now we can submit an ingress for the cheese websites. ```yaml apiVersion: extensions/v1beta1 kind: Ingress metadata: name: cheese spec: rules: - host: stilton.local http: paths: - path: / backend: serviceName: stilton servicePort: http - host: cheddar.local http: paths: - path: / backend: serviceName: cheddar servicePort: http - host: wensleydale.local http: paths: - path: / backend: serviceName: wensleydale servicePort: http ``` [examples/k8s/cheese-ingress.yaml](https://github.com/containous/traefik/tree/master/examples/k8s/cheese-ingress.yaml) > Notice that we list each hostname, and add a backend service. ```sh kubectl apply -f examples/k8s/cheese-ingress.yaml ``` Now visit the [Træfɪk dashboard](http://traefik-ui.local/) and you should see a frontend for each host. Along with a backend listing for each service with a Server set up for each pod. If you edit your `/etc/hosts` again you should be able to access the cheese websites in your browser. ```sh echo "$(minikube ip) stilton.local cheddar.local wensleydale.local" | sudo tee -a /etc/hosts ``` * [Stilton](http://stilton.local/) * [Cheddar](http://cheddar.local/) * [Wensleydale](http://wensleydale.local/) ## Path based routing Now lets suppose that our fictional client has decided that while they are super happy about our cheesy web design, when they asked for 3 websites they had not really bargained on having to buy 3 domain names. No problem, we say, why don't we reconfigure the sites to host all 3 under one domain. ```yaml apiVersion: extensions/v1beta1 kind: Ingress metadata: name: cheeses annotations: traefik.frontend.rule.type: pathprefixstrip spec: rules: - host: cheeses.local http: paths: - path: /stilton backend: serviceName: stilton servicePort: http - path: /cheddar backend: serviceName: cheddar servicePort: http - path: /wensleydale backend: serviceName: wensleydale servicePort: http ``` [examples/k8s/cheeses-ingress.yaml](https://github.com/containous/traefik/tree/master/examples/k8s/cheeses-ingress.yaml) > Notice that we are configuring Træfɪk to strip the prefix from the url path > with the `traefik.frontend.rule.type` annotation so that we can use > the containers from the previous example without modification. ```sh kubectl apply -f examples/k8s/cheeses-ingress.yaml ``` ```sh echo "$(minikube ip) cheeses.local" | sudo tee -a /etc/hosts ``` You should now be able to visit the websites in your browser. * [cheeses.local/stilton](http://cheeses.local/stilton/) * [cheeses.local/cheddar](http://cheeses.local/cheddar/) * [cheeses.local/wensleydale](http://cheeses.local/wensleydale/) ## Disable passing the Host header By default Træfɪk will pass the incoming Host header on to the upstream resource. There are times however where you may not want this to be the case. For example if your service is of the ExternalName type. To disable passing the Host header set the "traefik.frontend.passHostHeader" annotation on your ingress to "false". Here is an example ingress definition: ```yaml apiVersion: extensions/v1beta1 kind: Ingress metadata: name: example annotations: traefik.frontend.passHostHeader: "false" spec: rules: - host: example.com http: paths: - path: /static backend: serviceName: static servicePort: https ``` And an example service definition: ```yaml apiVersion: v1 kind: Service metadata: name: static spec: ports: - name: https port: 443 type: ExternalName externalName: static.otherdomain.com ``` If you were to visit example.com/static the request would then be passed onto static.otherdomain.com/static and static.otherdomain.com would receive the request with the Host header being static.otherdomain.com.