关于k8s 使用 Service 控制器对外暴露服务的问题
时间：2023-01-12 12:39:07|栏目：|点击： 次
Service 引入主要是解决 Pod 的动态变化，提供统一访问入口：
- 防止 Pod 失联，准备找到提供同一个服务的 Pod （服务发现）
- 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
