headless service 需要将 spec.clusterIP 设置成 None。
因为没有ClusterIP，kube-proxy 并不处理此类服务，因为没有load balancing或 proxy 代理设置，在访问服务的时候回返回后端的全部的Pods IP地址，主要用于开发者自己根据pods进行负载均衡器的开发(设置了selector) 或 StatefulSet.
$cat deployment.yaml apiVersion: extensions/v1beta1 kind: Deployment metadata: name: nginx-deployment spec: replicas: 2 # tells deployment to run 2 pods matching the template template: # create pods using pod definition in this template metadata: # unlike pod-nginx.yaml, the name is not included in the meta data as a unique name is # generated from the deployment name labels: app: nginx_test spec: containers: - name: nginx image: nginx:1.7.9 ports: - containerPort: 80
$ cat headless_service.yaml kind: Service apiVersion: v1 metadata: name: nginx-service spec: selector: app: nginx_test ports: - protocol: TCP port: 80 targetPort: 80 clusterIP: None
通过dns访问，会返回后端pods的列表
登录到Cluster的内部pod
nslookup nginx-service nslookup: can‘t resolve ‘(null)‘: Name does not resolve Name: nginx-service Address 1: 10.10.23.36 Address 2: 10.10.23.39
原文：https://www.cnblogs.com/vincenshen/p/9642156.html