标签：cluster vim 命令 str sbin 计算 and 扩展性 work
k8s中service组件有三个类型本篇内容着重对Nodeport类型进行示例；
创建一个nginx的Deployment
[root@master1 demo]# kubectl create deployment nginx-deployment --image=nginx1.8 --dry-run -o=yaml > nginx-deployment.yaml修改yaml文件
[root@master1 demo]# cat nginx-deployment.yaml
apiVersion: apps/v1
kind: Deployment
metadata:
labels:
app: nginx-deployment
name: nginx-deployment
spec:
replicas: 1
selector:
matchLabels:
app: nginx-deployment
template:
metadata:
labels:
app: nginx-deployment
spec:
containers:
- image: nginx:1.8
name: nginx
ports:
- containerPort: 80[root@master1 demo]# kubectl expose deployment nginx-deployment --protocol=TCP --port=80 --target-port=80 --type=NodePort --dry-run -o=yaml > nginx-deploy-service.yaml[root@master1 demo]# cat nginx-deploy-service.yaml
apiVersion: v1
kind: Service
metadata:
labels:
app: nginx-deployment
name: nginx-deployment
spec:
ports:
- port: 80
protocol: TCP
targetPort: 80
selector:
app: nginx-deployment
type: NodePortselector:
app: nginx-deployment
这个标签是对应的Deployment的app标签。
创建并查看service
[root@master1 demo]# kubectl create -f nginx-deploy-service.yaml
service/nginx-deployment created
[root@master1 demo]# kubectl get svc
NAME TYPE CLUSTER-IP EXTERNAL-IP PORT(S) AGE
kubernetes ClusterIP 10.0.0.1 <none> 443/TCP 6d7h
nginx-deployment NodePort 10.0.0.238 <none> 80:32256/TCP 5s[root@master1 demo]# curl 10.0.0.238 32256
<!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>
curl: (7) Failed to connect to 0.0.126.0: 无效的参数
如图所示
我们的集群replicas=1，scheduler通过计算绑定到172.16.1.76节点，NodePort端口为32256
NodePort类型的service组件会在每个Node节点都会监听32256端口，但是只能访问172.16.1.76节点才能正常访问，访问75和77节点就无法正常通信，那说明我们的iptables有问题
执行下列命令：
iptables -P FORWARD ACCEPT*就可以正常访问，但是这样修改iptables只能临时生效，重启node节点就会失效。
永久解决方案(修改docker.service文件，每次docker启动自动修改FORWARD链)：
[root@k8s-master ~]# vim /usr/lib/systemd/system/docker.service
[Service]
............
ExecStartPost=/sbin/iptables -I FORWARD -s 0.0.0.0/0 -j **ACCEPT**
systemctl daemon-reload
systemctl restart docker
k8s 1.9以后的版本建议使用ipvs的网络代理方案，它和iptables均基于netfilter
差异如下
k8s的NodePort类型的service组件以及遇到的问题
标签：cluster vim 命令 str sbin 计算 and 扩展性 work
原文地址：https://blog.51cto.com/liujingyu/2531496
