关于k8s 使用 Service 控制器对外暴露服务的问题

这篇文章主要介绍了k8s使用Service控制器对外暴露服务,包括部署deploy,部署 service及查看 service 和 pod 的关系,本文给大家介绍的非常详细,需要的朋友可以参考下

Service 引入主要是解决 Pod 的动态变化,提供统一访问入口:

  1. 防止 Pod 失联,准备找到提供同一个服务的 Pod (服务发现) 
  2. 定义一组 Pod 的访问策略 (负载均衡)

部署 deploy

kubectl apply -f deploy.yaml
apiVersion: apps/v1
kind: Deployment
metadata:
  name: chiyi-nginx
spec:
  replicas: 3
  selector:
    matchLabels:
      app: chiyi-nginx
  template:
    metadata:
      labels:
        app: chiyi-nginx
    spec:
      containers:
      - name: nginx
        image: nginx:1.14.2
        ports:
        - containerPort: 80

部署 service

kubectl apply -f service.yaml
apiVersion: v1
kind: Service
metadata:
  name: chiyi-nginx
spec:
  selector:
    app: chiyi-nginx
  ports:
    - protocol: TCP
      port: 80
      targetPort: 80
      nodePort: 30002
  type: NodePort

查看 service 和 pod 的关系

kubectl  get ep
curl 10.244.1.58:80

说明:

Service 通过标签关联一组 Pod

Service 为一组 Pod 提供负载均衡能力

[root@k8s-master service]# kubectl get ep
NAME          ENDPOINTS                                      AGE
chiyi-nginx   10.244.1.58:80,10.244.1.59:80,10.244.2.46:80   5m19s
kubernetes    172.17.28.225:6443                             23h
[root@k8s-master service]# curl 10.244.1.58:80
<!DOCTYPE html>
<html>
<head>
<title>Welcome to nginx!</title>
<style>
    body {
        width: 35em;
        margin: 0 auto;
        font-family: Tahoma, Verdana, Arial, sans-serif;
    }
</style>
</head>
<body>
<h1>Welcome to nginx!</h1>
<p>If you see this page, the nginx web server is successfully installed and
working. Further configuration is required.</p>
 
<p>For online documentation and support please refer to
<a href="http://nginx.org/">nginx.org</a>.<br/>
Commercial support is available at
<a href="http://nginx.com/">nginx.com</a>.</p>
 
<p><em>Thank you for using nginx.</em></p>
</body>
</html>

查看 service

kubectl  get service
curl 10.101.104.218
[root@k8s-master service]# kubectl get service
NAME          TYPE        CLUSTER-IP       EXTERNAL-IP   PORT(S)        AGE
chiyi-nginx   NodePort    10.101.104.218   <none>        80:30002/TCP   6m3s
kubernetes    ClusterIP   10.96.0.1        <none>        443/TCP        23h
[root@k8s-master service]# curl 10.101.104.218
<!DOCTYPE html>
<html>
<head>
<title>Welcome to nginx!</title>
<style>
    body {
        width: 35em;
        margin: 0 auto;
        font-family: Tahoma, Verdana, Arial, sans-serif;
    }
</style>
</head>
<body>
<h1>Welcome to nginx!</h1>
<p>If you see this page, the nginx web server is successfully installed and
working. Further configuration is required.</p>
 
<p>For online documentation and support please refer to
<a href="http://nginx.org/">nginx.org</a>.<br/>
Commercial support is available at
<a href="http://nginx.com/">nginx.com</a>.</p>
 
<p><em>Thank you for using nginx.</em></p>
</body>
</html>

查看端口

ss -antp |grep 30002

[root@k8s-master service]# ss -antp |grep 30002
LISTEN     0      128          *:30002                    *:*                   users:(("kube-proxy",pid=3544,fd=13))

导出 yaml

kubectl  get service chiyi-nginx -o yaml

筛选 service 关联 pod

kubectl get pods -l app=chiyi-nginx
[root@k8s-master service]# kubectl get pods -l app=chiyi-nginx
NAME                           READY   STATUS    RESTARTS   AGE
chiyi-nginx-5bbf8bff4b-6bwfz   1/1     Running   0          3m58s
chiyi-nginx-5bbf8bff4b-bpvvc   1/1     Running   0          3m58s
chiyi-nginx-5bbf8bff4b-pwwt4   1/1     Running   0          3m58s

扩容测试

kubectl scale deployment chiyi-nginx --replicas=1
kubectl  get service,pods,ep

Service 三种常用类型

  • ClusterIP 集群内部使用,任一节点服务器和 pod 内部都可以访问
  • NodePort 对外暴露应用(端口默认范围:30000-32767),任一节点服务器公网IP+端口号,可在浏览器访问。
  • LoadBalancer 对外暴露应用,适合公有云

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