Enabling a LoadBalancer Service to Obtain the Client IP Address

When creating a LoadBalancer Service using a shared load balancer, you can configure annotations for the load balancer listeners to obtain the client IP address.

If a dedicated load balancer is used, the function of obtaining the client IP address is enabled by default.
After the function of obtaining the client IP address is enabled, if you delete the target annotation from the YAML file, the configuration on the ELB will be retained.

Prerequisites

A Kubernetes cluster is available and the cluster version meets the following requirements:
- v1.23: v1.23.17-r0 or later
- v1.25: v1.25.12-r0 or later
- v1.27: v1.27.9-r0 or later
- v1.28: v1.28.7-r0 or later
- v1.29: v1.29.3-r0 or later
- Other clusters of later versions
The cluster can be accessed using kubectl. For details, see Connecting to a Cluster Using kubectl.

Notes and Constraints

In CCE standard clusters, this setting takes effect only when Service affinity is set to the node level affinity (with externalTrafficPolicy set to Local).

In CCE Turbo clusters, this setting cannot take effect, because Service affinity cannot be set to the node level affinity and externalTrafficPolicy cannot be set to Local.

Using kubectl

An example YAML file of a Service created using an existing load balancer is as follows:

apiVersion: v1 
kind: Service 
metadata: 
  name: nginx
  annotations:
    kubernetes.io/elb.id: <your_elb_id>              # Load balancer ID. Replace it with the actual value.
    kubernetes.io/elb.class: union                   # Load balancer type
    kubernetes.io/elb.transparent-client-ip: 'true'  # Enable the function of obtaining the client source IP address.
spec:
  selector: 
     app: nginx
  externalTrafficPolicy: Local
  ports: 
  - name: service0 
    port: 80
    protocol: TCP 
    targetPort: 80
  type: LoadBalancer

**Table 1** Key parameters
Parameter	Type	Description
kubernetes.io/elb.transparent-client-ip	String	This parameter can be configured only for TCP/UDP Services. true: Enabling the function of obtaining the client source IP address. false: Disabling the function of obtaining the client source IP address.