Configuring a Custom Header Forwarding Policy for a LoadBalancer Ingress

Prerequisites

Using kubectl

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 created using an existing load balancer is as follows:

   apiVersion: networking.k8s.io/v1
   kind: Ingress
   metadata:
     name: ingress-test
     namespace: default
     annotations:
       kubernetes.io/elb.port: '80'
       kubernetes.io/elb.id: 08eab934-1636-4d90-a4cd-cb3fa4330411
       kubernetes.io/elb.class: performance  # A dedicated load balancer is required.
       # Path /a can be accessed only through Header key1=value1 or key1=value2. The accessed Service is svc-a:80.
       kubernetes.io/elb.headers.svc-a: | 
         {
             "key": "key1",
             "values": [
                 "value1",
                 "value2"
             ]
         }
       # Path /b can be accessed only through Header key2=value1 or key2=value2. The accessed Service is svc-b:81.
       kubernetes.io/elb.headers.svc-b: |  
         {
             "key": "key2",
             "values": [
                 "value1",
                 "value2"
             ]
         }
   spec:
     rules:
       - host: ''
         http:
           paths:
             - path: /a
               backend:
                 service:
                   name: svc-a
                   port:
                     number: 80
               property:
                 ingress.beta.kubernetes.io/url-match-mode: STARTS_WITH
               pathType: ImplementationSpecific
             - path: /b
               backend:
                 service:
                   name: svc-b
                   port:
                     number: 81
               property:
                 ingress.beta.kubernetes.io/url-match-mode: STARTS_WITH
               pathType: ImplementationSpecific
     ingressClassName: cce

   Table 1 Annotations for configuring a custom header forwarding policy

   Parameter	Type	Description
   kubernetes.io/elb.headers.${svc_name}	String	Custom header of the Service associated with an ingress. ${svc_name} is the Service name. Format: a JSON string, for example, {"key": "test", "values": ["value1", "value2"]} key/value indicates the key-value pair of the custom header. A maximum of eight values can be configured. Enter 1 to 40 characters for a key. Only letters, digits, hyphens (-), and underscores (_) are allowed. Enter 1 to 128 characters for a value. Asterisks (*) and question marks (?) are allowed, but spaces and double quotation marks are not allowed. An asterisk can match zero or more characters, and a question mark can match one character. After a custom header forwarding policy is configured for an ingress, a grayscale release policy cannot be created for the ingress. Enter 1 to 51 characters for ${svc_name}.

3. Create an ingress.

   kubectl create -f ingress-test.yaml

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

   ingress/ingress-test 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
   ingress-test  cce      *         121.**.**.**     80      10s