Kubernetes的ExternalName详解

ExternalName类型的Service在Kubernetes中用于将外部服务（不是Kubernetes集群内的服务）映射到Kubernetes集群内的Service。

样例

其创建方法如下：

kind: Service
apiVersion: v1
metadata:
  name: my-external-service
  namespace: cv-console-dev
  labels:
    app: my-external-service
  annotations:
    kubesphere.io/creator: sunjq
    kubesphere.io/serviceType: externalservice
spec:
  type: ExternalName
  sessionAffinity: None
  externalName: www.httpclient.cn

在上述配置中，我们创建了一个名为my-external-service的Service，其类型为ExternalName，并将www.httpclient.cn映射到该Service。这就相当于在Kubernetes集群内部创建了一个别名，可以通过访问my-external-service来访问www.httpclient.cn。

需要注意的是，使用ExternalName类型的Service需要确保目标外部服务已经存在，并且可以通过域名进行访问。

测试过程

root@5c856df78-5ml9f:/# curl -k  test-ex.cv-console-dev -vvv
*   Trying 47.244.242.115:80...
* Connected to test-ex.cv-console-dev (47.244.242.115) port 80 (#0)     ---------------------外部的域名对应的ip
> GET / HTTP/1.1
> Host: test-ex.cv-console-dev
> User-Agent: curl/7.74.0
> Accept: */*
>
* Mark bundle as not supporting multiuse
< HTTP/1.1 200 OK
< Server: nginx/1.15.12
< Date: Thu, 31 Aug 2023 08:49:05 GMT
< Content-Type: text/html
< Content-Length: 612
< Last-Modified: Fri, 21 Jun 2019 06:42:16 GMT
< Connection: keep-alive
< ETag: "5d0c7c48-264"
< Accept-Ranges: bytes
<







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* Connection #0 to host test-ex.cv-console-dev left intact