Advanced content routing for Kubernetes Ingress using the HTTPRoute CRD¶
Kubernetes native Ingress offers basic host and path-based routing which is supported by the Citrix ingress controller. Citrix also provides an alternative approach using content routing CRDs for supporting advanced routing capabilities. Content Routing CRDs include Listener CRD and HTTPRoute CRD. These CRDs provide advanced content routing features such as regex based expression and content switching based on query parameters, cookies, HTTP headers, and other Citrix ADC custom expressions.
With the Ingress version
networking.k8s.io/v1, Kubernetes introduces support for resource backends. A resource backend is an
ObjectRef to another Kubernetes resource within the same namespace as an Ingress object.
Now, Citrix supports configuring the HTTP route CRD resource as a resource backend in Ingress. By default, Ingress supports only limited content routing capabilities like path and host-based routing. With this feature, you can extend advanced content routing capabilities to Ingress and configure various content switching options. For a given domain, you can use the
HTTPRoute custom resource to configure content switching without losing the third party compatibility support of the Kubernetes Ingress API.
Note: This feature supports the Kubernetes Ingress version
networking.k8s.io/v1 that is available on Kubernetes 1.19 and later versions.
Note: If the Ingress path routing and
HTTPRoute are used for the same domain, all the content routing policies from the
HTTPRoute resource get lower priority than the Ingress based content routing policies. So, it is recommended to configure all the content switching policies of the
HTTPRoute resource for a given domain if advanced content routing is required.
Configure advanced content routing for Kubernetes Ingress using the HTTPRoute CRD¶
This procedure shows how to deploy an HTTPRoute resource as a resource backend to support advanced content routing.
- Ensure that the ingress API version
networking.k8s.io/v1is available in the Kubernetes cluster.
- Ensure that the HTTPRoute CRD is deployed.
Deploy the Ingress resource¶
Define the Ingress resource with the resource back-end pointing to a
HTTPRoute custom resource in a YAML file. Specify all the front-end configurations such as certificates, front-end profiles, front-end IP address, and ingress class as part of the Ingress resource.
Following is a sample Ingress resource named as
apiVersion: networking.k8s.io/v1 kind: Ingress metadata: name: kuard-ingress annotations: ingress.citrix.com/frontend-ip: "x.x.x.x" kubernetes.io/ingress.class: citrix ingress.citrix.com/insecure-termination: "redirect" spec: tls: - secretName: web-ingress-secret rules: - host: kuard.example.com http: paths: - pathType: ImplementationSpecific backend: resource: apiGroup: citrix.com kind: HTTPRoute name: kuard-example-route
After defining the Ingress resource in a YAML file, deploy the YAML file using the following command. Here,
sample-ingress.yaml is the YAML file definition.
Kubectl apply -f sample-ingress.yaml
In this example, content switching policies for the domain
kuard.example.com are defined as part of the
HTTPRoute custom resource called
ingress class are specified as part of the Ingress resource. Back-end annotations such as load balancing method and service group configurations are specified as part of the
HTTPRoute custom resource.
Deploy the HTTPRoute resource¶
Define the HTTP route configuration in a YAML file. In the YAML file, use HTTPRoute in the
kind field and in the
spec section add the
HTTPRoute CRD attributes based on your requirement for the HTTP route configuration.
For more information about API description and examples, see the HTTPRoute documentation.
Following is a sample
HTTPRoute resource configuration. This example shows how to use query parameters based content switching for the various Kubernetes back-end microservices.
apiVersion: citrix.com/v1 kind: HTTPRoute metadata: name: kuard-example-route spec: hostname: - kuard.example.com rules: - name: kuard-blue match: - queryParams: - name: version contains: v2 action: backend: kube: service: kuard-blue port: 80 - name: kuard-green match: - queryParams: - name: version contains: v3 action: backend: kube: service: kuard-green port: 80 - name: kuard-default match: - path: prefix: / action: backend: kube: service: kuard-purple port: 80
After you have defined the HTTP routes in the YAML file, deploy the YAML file. In this example,
httproute is the YAML definition.
Kubectl apply -f httproute.yaml