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Volcengine Kubernetes Engine

Service

ExternalName

ExternalName maps an internal service name to an external domain name within a cluster, allowing Pods in the cluster to access the external domain name using the Service name. This topic describes how to configure a service of the ExternalName type.

Background

When you create a Service of the ExternalName type in a cluster, Kubernetes does not assign a ClusterIP to the Service or create Endpoints. Instead, Kubernetes uses CoreDNS to return a CNAME record that maps the service name to an external DNS domain name. Workloads inside the cluster can access external services using the Service name (for example, service-demo.default.svc.cluster.local), without hardcoding the external domain name in the application.

Procedure

tip

Before configuring an ExternalName Service using the kubectl command-line interface, ensure that the following conditions are met:

The kubectl tool has been installed on your on-premises computer. For details, see Installing and configuring kubectl.

The target cluster has been connected through kubectl. For details, see Connecting to clusters.

Create a YAML file for the service. The following external-service-demo.yaml file serves as an example:

apiVersion: v1
kind: Service
metadata:
name: external-service-demo # The name of the service.
namespace: default # The namespace to which the service belongs.
spec:
type: ExternalName # The Service type is set to ExternalName.
externalName: volcengine.com # The external domain name to map to outside the cluster. It must be a valid DNS name. IP addresses are not allowed.

Run the following command to create a Service.

kubectl apply -f external-service-demo.yaml

Validate results

Viewing services

The service you created can be found in the service list.

Testing the connections to services

After the Service is created, you can access the external domain name using the Service name. You can run the following command inside the Pod to validate domain name resolution and connectivity.

The expected resolution results include a CNAME record for volcengine.com, as well as the resolved real IP address, indicating that the ExternalName mapping has taken effect.

Last updated: 2026.09.03 15:58:27