Configuring an HTTP/HTTPS Header for a LoadBalancer Service

HTTP headers are a list of strings sent and received by both the client and server on every HTTP request and response. This section describes HTTP headers supported by HTTP and HTTP listeners.

HTTP/HTTPS headers rely on ELB. Before using HTTP/HTTPS headers in a Service, check whether HTTP/HTTPS headers are supported in the current region. For details, see HTTP/HTTPS Headers.
After HTTP or HTTPS is configured, if you delete the HTTP or HTTPS configuration on the CCE console or delete the target annotation from the YAML file, the configuration on the ELB will be retained.

**Table 1** Headers
Header	Feature	Description
X-Forwarded-Port	Transfer Listener Port Number	If this option is enabled, the port number used by the listener will be transmitted to backend servers through the X-Forwarded-Port header.
X-Forwarded-For-Port	Transfer Port Number in the Request	If this option is enabled, the port number used by the client will be transmitted to backend servers through the X-Forwarded-For-Port header.
X-Forwarded-Host	Rewrite X-Forwarded-Host	If this function is enabled, X-Forwarded-Host will be rewritten using the Host field in the client request body and transferred to backend servers.

Prerequisites

A Kubernetes cluster is available and the cluster version meets the following requirements:
- v1.23: v1.23.13-r0 or later
- v1.25: v1.25.8-r0 or later
- v1.27: v1.27.5-r0 or later
- v1.28: v1.28.3-r0 or later
- Other clusters of later versions

To create a cluster using commands, ensure kubectl is used. For details, see Connecting to a Cluster Using kubectl.

Using the CCE Console

Log in to the CCE console and click the cluster name to access the cluster console.
In the navigation pane, choose Services & Ingresses. In the upper right corner, click Create Service.

Configure Service parameters. In this example, only mandatory parameters are listed. For details about how to configure other parameters, see Creating a LoadBalancer Service.

Service Name: Specify a Service name, which can be the same as the workload name.
Service Type: Select LoadBalancer.
Selector: Add a label and click Confirm. The Service will use this label to select pods. You can also click Reference Workload Label to use the label of an existing workload. In the dialog box that is displayed, select a workload and click OK.
Load Balancer: Select a load balancer type and creation mode.
- In this example, only dedicated load balancers are supported, and the type of the load balancer must be Application (HTTP/HTTPS) or Network (TCP/UDP/TLS) & Application (HTTP/HTTPS). Otherwise, HTTP or HTTPS cannot be enabled on the listener port.
- This section uses an existing load balancer as an example. For details about the parameters for automatically creating a load balancer, see Table 1.
Ports
- Protocol: Select TCP. If you select UDP, HTTP and HTTPS will be unavailable.
- Service Port: port used by the Service. The port number ranges from 1 to 65535.
- Container Port: listener port of the workload. For example, Nginx uses port 80 by default.
- Frontend Protocol: In this example, select HTTP or HTTPS for the Service.

Listener

Advanced Options: Select a proper option.

Configuration	Description	Restrictions
Transfer Listener Port Number	If this function is enabled, the listening port on the load balancer can be transferred to backend servers through the HTTP header of the packet.	This parameter is available only after HTTP/HTTPS is enabled on the listener port of a dedicated load balancer.
Transfer Port Number in the Request	If this function is enabled, the source port of the client can be transferred to backend servers through the HTTP header of the packet.	This parameter is available only after HTTP/HTTPS is enabled on the listener port of a dedicated load balancer.
Rewrite X-Forwarded-Host	If this function is enabled, X-Forwarded-Host will be rewritten using the Host field in the client request body and transferred to backend servers.	This parameter is available only after HTTP/HTTPS is enabled on the listener port of a dedicated load balancer.

Figure 1 Configuring HTTP/HTTPS headers
Click to enlarge

Click OK.

Using kubectl

This section uses an existing load balancer as an example. An example YAML file of a Service with HTTP/HTTPS header enabled is as follows:

apiVersion: v1
kind: Service
metadata:
  name: test
  labels:
    app: nginx
  namespace: default
  annotations:
    kubernetes.io/elb.class: performance                              # Load balancer type, which can only be performance (dedicated load balancer)
    kubernetes.io/elb.id: 35cb350b-23e6-4551-ac77-10d5298f5204        # ID of an existing load balancer
    kubernetes.io/elb.x-forwarded-port: 'true'                       # Obtain the listener port number.
    kubernetes.io/elb.x-forwarded-for-port: 'true'                   # Obtain the client port number for requests.
    kubernetes.io/elb.x-forwarded-host: 'true'                       # Rewrite X-Forwarded-Host.
spec:
  selector:
    app: nginx
  externalTrafficPolicy: Cluster
  ports:
    - name: cce-service-0
      targetPort: 80
      nodePort: 0
      port: 80
      protocol: TCP
  type: LoadBalancer
  loadBalancerIP: **.**.**.**    # IP address of the load balancer

**Table 2** Key parameters
Parameter	Type	Description
kubernetes.io/elb.x-forwarded-port	String	A load balancer can obtain the port number of a listener using X-Forwarded-Port and transmit the port number to the packets of the backend server. true: Enable the function of obtaining a listener port number. false: Disable the function of obtaining a listener port number.
kubernetes.io/elb.x-forwarded-for-port	String	A load balancer can obtain a client port number for requests using X-Forwarded-For-Port and transmit the port number to the packets of the backend server. true: Enable the function of obtaining a client port number for requests. false: Disable the function of obtaining a client port number for requests.
kubernetes.io/elb.x-forwarded-host	String	true: Enable the function of rewriting X-Forwarded-Host. Then, the X-Forwarded-Host header will be rewritten using the Host header of the client request and transmitted to backend servers. false: Disable the function of rewriting X-Forwarded-Host. Then, the X-Forwarded-Host header of the client will be transmitted to backend servers.