k8s之service
使用deploy-nginx.yaml创建控制器
apiVersion: apps/v1 kind: Deployment metadata: name: nginx namespace: dev spec: replicas: 3 selector: matchLabels: run: nginx template: metadata: labels: run: nginx spec: containers: - image: nginx:1.17.1 name: nginx ports: - containerPort: 80 protocol: TCP [root@master ~]# kubectl create -f deploy-nginx.yaml deployment.apps/nginx created
查看pod列表
[root@master ~]# kubectl get pod -n dev -o wide NAME READY STATUS RESTARTS AGE IP NODE NOMINATED NODE READINESS GATES nginx-64777cd554-4m2nj 1/1 Running 0 3m30s 10.244.1.15 node2 <none> <none> nginx-64777cd554-lp8v2 1/1 Running 0 3m30s 10.244.1.16 node2 <none> <none> nginx-64777cd554-w2m2t 1/1 Running 0 3m30s 10.244.2.9 node1 <none> <none>
删除其中一个pod
[root@master ~]# kubectl delete pod nginx-64777cd554-4m2nj -n dev pod "nginx-64777cd554-4m2nj" deleted
查看新的pod
[root@master ~]# kubectl get pod -n dev -o wide NAME READY STATUS RESTARTS AGE IP NODE NOMINATED NODE READINESS GATES nginx-64777cd554-lp8v2 1/1 Running 0 7m32s 10.244.1.16 node2 <none> <none> nginx-64777cd554-rlbm8 1/1 Running 0 47s 10.244.1.17 node2 <none> <none> nginx-64777cd554-w2m2t 1/1 Running 0 7m32s 10.244.2.9 node1 <none> <none>
发现ip地址和以前不一样了
Service介绍
虽然每个pod都会分配一个单独的pod ip，然而却存在如下问题：
- pod ip 会随着pod的重建产生变化
- pod ip仅仅是集群内可见的虚拟ip，外部无法访问
这样对于访问这个服务带来了难度，因此k8s设计了service来解决这个问题
service可以看作是一组同类pod对外的访问接口，借助service，应用可以方便地实现服务发现和负载均衡
创建集群内部可访问的service
暴露service
[root@master ~]# kubectl expose deployment nginx --name=svc-nginx1 --type=ClusterIP --port=80 --target-port=80 -n dev service/svc-nginx1 exposed [root@master ~]# kubectl get service -n dev NAME TYPE CLUSTER-IP EXTERNAL-IP PORT(S) AGE svc-nginx1 ClusterIP 10.100.210.11 <none> 80/TCP 44s #这里产生了一个ClusterIP，这就是service的ip，在service的生命周期中，这个地址是不会变的，可以通过这个Ip访问当前service对应的pod
#访问service [root@master ~]# curl 10.100.210.11:80 <!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>
创建集群外部也可以访问的service
上面搭建的service的type类型为ClusterIP，这个ip地址只能集群内部可访问
如果需要创建外部也可以访问的Service，需要修改type为NodePort
[root@master ~]# kubectl expose deploy nginx --name=svc-nginx2 --type=NodePort --port=80 --target-port=80 -n dev service/svc-nginx2 exposed [root@master ~]# kubectl get svc -n dev NAME TYPE CLUSTER-IP EXTERNAL-IP PORT(S) AGE svc-nginx1 ClusterIP 10.100.210.11 <none> 80/TCP 20m svc-nginx2 NodePort 10.104.222.53 <none> 80:32714/TCP 67s
在浏览器中访问
删除service
[root@master ~]# kubectl delete svc svc-nginx2 -n dev service "svc-nginx2" deleted [root@master ~]# kubectl delete svc svc-nginx1 -n dev service "svc-nginx1" deleted
使用配置方式
apiVersion: v1 kind: Service metadata: name: svc-nginx namespace: dev spec: ports: - port: 80 protocol: TCP targetPort: 80 selector: run: nginx type: ClusterIP
使用配置文件
[root@master ~]# vim svc-nginx.yaml [root@master ~]# kubectl create -f svc-nginx.yaml service/svc-nginx created [root@master ~]# kubectl get svc -n dev NAME TYPE CLUSTER-IP EXTERNAL-IP PORT(S) AGE svc-nginx ClusterIP 10.102.204.135 <none> 80/TCP 14s
删除
[root@master ~]# kubectl delete -f svc-nginx.yaml service "svc-nginx" deleted [root@master ~]# kubectl get svc -n dev No resources found in dev namespace.
