Configuring URL Rewriting for a LoadBalancer Ingress

1. Log in to the CCE console and click the cluster name to access the cluster console.
2. Choose Services & Ingresses in the navigation pane, click the Ingresses tab, and click Create Ingress in the upper right corner.
3. Configure ingress parameters.
   

   This example explains only key parameters for configuring rewrite. You can configure other parameters as required. For details, see Creating a LoadBalancer Ingress on the Console.

   Table 1 Key parameters

   Parameter	Description	Example
   Name	Enter an ingress name.	ingress-test
   Load Balancer	Select a load balancer to be associated with the ingress or automatically create a load balancer. In this example, only dedicated load balancers are supported.	Dedicated
   Listener	External Protocol: HTTP and HTTPS are available. External Port: specifies the port of the load balancer listener.	External Protocol: HTTP External Port: 80
   Forwarding Policy	Domain Name: Enter an actual domain name to be accessed. If it is left blank, the ingress can be accessed through the IP address. Ensure that the domain name has been registered and licensed. Once a forwarding policy is configured with a domain name specified, you must use the domain name for access. Path Matching Rule: Select RegEx match if URL rewriting is used. Path: Enter the path provided by a backend application for external access. The path added must be valid in the backend application, or the forwarding cannot take effect. Destination Service: Select an existing Service or create a Service. Any Services that do not match the search criteria will be filtered out automatically. Destination Service Port: Select the access port of the destination Service. Actions Operation: Select Rewrite URL. When an access request meets the forwarding policy, the URL will be rewritten based on the matching rule. You are allowed to configure a regular expression for the patch matching rule, and the result obtained using the regular expression can be used for rewriting the URL. Path: A proper rule matching a regular expression must start with a slash (/).	Domain Name: example.com Path Matching Rule: RegEx match Path: /first/(.*)/(.*)/end Destination Service: nginx Destination Service Port: 80 Actions: Operation: Rewrite URL Path: /$1/$2

   Figure 1 Configuring a URL rewriting rule for an ingress
   

4. Click OK.

URL rewriting rules of an ingress can be configured using annotations. The following is an example:

1. Use kubectl to access the cluster. For details, see Connecting to a Cluster Using kubectl.
2. Create a YAML file named ingress-test.yaml. The file name can be customized.

   vi ingress-test.yaml

   An example YAML file of an ingress associated with an existing load balancer is as follows:

   apiVersion: networking.k8s.io/v1
   kind: Ingress
   metadata:
     name: test-rewrite-url
     namespace: default
     annotations:
       kubernetes.io/elb.id: df76342f-e898-402a-bac8-bde5bf974da8
       kubernetes.io/elb.class: performance
       kubernetes.io/elb.port: '80'
       kubernetes.io/elb.rewrite-target: /$1/$2       # Rewrite path
   spec:
     rules:
       - host: "example.com"
         http:
           paths:
             - path: /first/(.*)/(.*)/end      # This path will be rewritten.
               backend:
                 service:
                   name: test-service
                   port:
                     number: 80
               property:
                 ingress.beta.kubernetes.io/url-match-mode: REGEX
               pathType: ImplementationSpecific
     ingressClassName: cce

   Table 2 Key parameters

   Parameter	Mandatory	Type	Description
   kubernetes.io/elb.rewrite-target	Yes	String	Information about the rewritten path. Format: A proper rule matching a regular expression must start with a slash (/). Parameter: This configuration takes effect on the URL of a single ingress matching the regular expression. After the configuration is deleted, the target URL rewriting rule will be automatically cleared. Either this annotation or the annotation of a grayscale release can be configured.

3. Create an ingress.

   kubectl create -f ingress-test.yaml

   If information similar to the following is displayed, the ingress has been created:

   ingress/test-rewrite-url created

4. Check the created ingress.

   kubectl get ingress

   If information similar to the following is displayed, the ingress has been created:

   NAME              CLASS    HOSTS     ADDRESS          PORTS   AGE
   test-rewrite-url  cce      *         121.**.**.**     80      10s

5. Use curl to verify the rewriting, where ${ELB_IP} is the IP address accessed by the target ingress.

   # curl -H "Host:example.com" ${ELB_IP}/first/aaa/bbb/end

   The access path will be rewritten to /aaa/bbb.