It was in June of last year that we first discussed the movement inside the Kubernetes community to develop an improved method of defining and managing ingress traffic for Kubernetes. That effort bore fruit in the form of the new Service APIs.
We introduced initial support for the Service APIs in Traefik 2.4 in January. This post will demonstrate how to use the new Gateway, GatewayClass, and HTTPRoute APIs with Traefik to route requests to services.
Prerequisites
Of course, you'll need some things before you begin:
- A working Kubernetes cluster, which this guide assumes is running on
localhost - The
kubectlcommand-line tool, installed and configured to access your cluster
You do not need to have Traefik installed on your cluster before you begin. You'll take care of that in the next few steps.
You'll also want the set of configuration files that accompanies this post, which are available on GitHub. Clone the repository like so:
git clone https://github.com/traefik-tech-blog/k8s-service-apis
Installing the CRDs
At the present time, the Service APIs are not installed on Kubernetes clusters by default. Support for them depends upon a set of custom resource definitions (CRDs), and you should make sure these are installed before enabling support in Traefik.
It's a safe bet to use the current released version, 0.10:
kubectl apply -k "github.com/kubernetes-sigs/service-apis/config/crd?ref=v0.1.0"
Install and Configure Traefik to Use Service APIs
To install Traefik v2.4 (or later) and have it configured to enable the new provider, the best way is to use the official Helm chart:
helm repo add traefik https://helm.traefik.io/traefik
helm repo update
helm install traefik --set experimental.kubernetesGateway.enabled=true traefik/traefik
Note the --set experimental.kubernetesGateway.enabled=true flag. This will install Traefik 2.4, enable the new Service APIs provider, and also create GatewayClasses and a Gateway instance.
More customization options for the installation, such as the label selector or TLS certificates (which you'll use later in this demonstration) are visible in the Helm chart's values file.
To verify that the new features are enabled, use port forwarding to expose the Traefik dashboard:
kubectl port-forward $(kubectl get pods --selector "app.kubernetes.io/name=traefik" --output=name) 9000:9000
When you use your browser to access the dashboard via http://localhost:9000/dashboard/, you should see that the KubernetesGateway provider is activated and ready to serve:
Setup a Dummy Service
You'll need a target where Traefik can route requests, so quickly install the famous whoami service using kubectl apply -f, in order to have something to use for testing purposes:
# 01-whoami.yaml
---
kind: Deployment
apiVersion: apps/v1
metadata:
name: whoami
spec:
replicas: 2
selector:
matchLabels:
app: whoami
template:
metadata:
labels:
app: whoami
spec:
containers:
- name: whoami
image: traefik/whoami:v1.6.0
ports:
- containerPort: 80
name: http
---
apiVersion: v1
kind: Service
metadata:
name: whoami
spec:
ports:
- protocol: TCP
port: 80
targetPort: http
selector:
app: whoami
Deploying a Simple Host
Now that everything is setup, you're ready to start the action the Service APIs way. Where previously you would have created an Ingress or IngressRoute, here you'll deploy your first simple HTTPRoute:
# 02-whoami-httproute.yaml
---
kind: HTTPRoute
apiVersion: networking.x-k8s.io/v1alpha1
metadata:
name: http-app-1
namespace: default
labels:
app: traefik
spec:
hostnames:
- "whoami"
rules:
- matches:
- path:
type: Exact
value: /
forwardTo:
- serviceName: whoami
port: 80
weight: 1
This HTTPRoute will catch requests made to the whoami hostname and forward them to the whoami service you deployed earlier. If you now make a request for that hostname, you will see typical whoami output, which looks something like this:
curl -H "Host: whoami" http://localhost
Hostname: whoami-9cdc57b6d-pfpxs
IP: 127.0.0.1
IP: ::1
IP: 10.42.0.13
IP: fe80::9c1a:a1ff:fead:2663
RemoteAddr: 10.42.0.11:33658
GET / HTTP/1.1
Host: whoami
User-Agent: curl/7.64.1
Accept: */*
Accept-Encoding: gzip
X-Forwarded-For: 10.42.0.1
X-Forwarded-Host: whoami
X-Forwarded-Port: 80
X-Forwarded-Proto: http
X-Forwarded-Server: traefik-74d7f586dd-xxr7r
X-Real-Ip: 10.42.0.1
Pay attention to the app: traefik label selector, which ensures that requests are routed to your Traefik instance. This is the default label that is set during the installation phase described above, but it can also be customized via the Helm chart.
Simple Host with Paths
The example above can easily be enhanced to only react on a given subpath:
# 03-whoami-httproute-paths.yaml
---
apiVersion: networking.x-k8s.io/v1alpha1
kind: HTTPRoute
metadata:
labels:
app: traefik
name: http-app-1
namespace: default
spec:
hostnames:
- whoami
rules:
-
forwardTo:
-
port: 80
serviceName: whoami
weight: 1
matches:
-
path:
type: Exact
value: /foo
With the modified HTTPRoute, you'll see that the previous request now returns a 404 error, while requesting the /foo path suffix returns success:
curl -H "Host: whoami" http://localhost/foo
Hostname: whoami-9cdc57b6d-pfpxs
IP: 127.0.0.1
IP: ::1
IP: 10.42.0.13
IP: fe80::9c1a:a1ff:fead:2663
RemoteAddr: 10.42.0.11:34424
GET /foo HTTP/1.1
Host: whoami
User-Agent: curl/7.64.1
Accept: */*
Accept-Encoding: gzip
X-Forwarded-For: 10.42.0.1
X-Forwarded-Host: whoami
X-Forwarded-Port: 80
X-Forwarded-Proto: http
X-Forwarded-Server: traefik-74d7f586dd-xxr7r
X-Real-Ip: 10.42.0.1
More information about what parts of a request can be matched can be found in the official Service API documentation.
TLS with Static Certificates
So far, you have created a simple HTTPRoute. For the next step, you'll want to secure this route through TLS. For that, you need to create a Kubernetes Secret first with a dummy certificate. You'll find one included in the configuration files in this post's GitHub repository:
# 04-tls-dummy-cert.yaml
---
apiVersion: v1
data:
tls.crt: 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
tls.key: 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
kind: Secret
metadata:
name: mysecret
namespace: default
type: kubernetes.io/tls
With that secret in place, you can start securing. First, you must reconfigure the Gateway to create a TLS listener with mysecret certificate. You can achieve this by using the upgrade option with the Helm chart to add a certificates section to your Traefik configuration:
helm upgrade traefik -f 05-values.yaml traefik/traefik
# 05-values.yaml
---
experimental:
kubernetesGateway:
appLabelSelector: traefik
certificates:
-
group: "core"
kind: "Secret"
name: "mysecret"
enabled: true
Once Traefik has restarted, you can check the results. The same HTTPRoute is still in effect, only now you can access it with HTTPS:
curl --insecure -H "Host: whoami" https://localhost/foo
Hostname: whoami-9cdc57b6d-pfpxs
IP: 127.0.0.1
IP: ::1
IP: 10.42.0.13
IP: fe80::9c1a:a1ff:fead:2663
RemoteAddr: 10.42.0.11:53158
GET /foo HTTP/1.1
Host: whoami
User-Agent: curl/7.64.1
Accept: */*
Accept-Encoding: gzip
X-Forwarded-For: 10.42.0.1
X-Forwarded-Host: whoami
X-Forwarded-Port: 443
X-Forwarded-Proto: https
X-Forwarded-Server: traefik-74d7f586dd-xxr7r
X-Real-Ip: 10.42.0.1
Note that you must pass the --insecure parameter to curl in order to use the unsigned dummy certificate.
Canary Releases
Another feature that Traefik 2.4 can support via the Service API specification is canary releases. Suppose you want to run two different services (or two versions of the same service) on one endpoint and route a portion of requests to each. You can achieve this by modifying your HTTPRoute.
First, you'll need a second service to run. For the sake of this example, you can quickly spawn an instance of Nginx:
# 06-nginx.yaml
---
kind: Deployment
apiVersion: apps/v1
metadata:
name: nginx
spec:
replicas: 2
selector:
matchLabels:
app: whoami
template:
metadata:
labels:
app: nginx
spec:
containers:
- name: whoami
image: nginx
ports:
- containerPort: 80
name: http
---
apiVersion: v1
kind: Service
metadata:
name: whoami
spec:
ports:
- protocol: TCP
port: 80
targetPort: http
selector:
app: nginx
The HTTPRoute resource has a weight option, and you can assign different values to each of the two services:
# 07-whoami-nginx-canary.yaml
---
apiVersion: networking.x-k8s.io/v1alpha1
kind: HTTPRoute
metadata:
labels:
app: traefik
name: http-app-1
namespace: default
spec:
hostnames:
- whoami
rules:
-
forwardTo:
-
port: 80
serviceName: whoami
weight: 3
-
port: 80
serviceName: nginx
weight: 1
Now, you'll once again be able to access your whoami service at http://localhost (without the foo/ path suffix), but 25% of the time you'll see a response from Nginx, rather than from whoami.
Known Limitations and the Future
Currently, Traefik's implementation of the Service APIs is focused on HTTP and HTTPS only. However, the spec also features TCP and in the future it will probably support UDP, as well. These are features the Traefik team will be working on.
In the meantime, you can get started using the Kubernetes Service APIs with Traefik 2.4 today. Explore away, and be sure to share your feedback. If you'd like to learn more about how Traefik is the perfect partner for your Kubernetes journey, check out our white paper on pairing Traefik with Kubernetes for microservices and modern, cloud-native application architectures.
This is a companion discussion topic for the original entry at https://traefik.io/blog/getting-started-with-traefik-and-the-new-kubernetes-service-apis/