5分钟带你体验kubernetes 对外提供访问

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作者声明：本篇文章系本人依照真实部署过程原创，未经许可，谢绝转载。

上一篇文章介绍了kubernetes kubernetes RollingUpdate滚动升级镜像回滚，这一篇文章带你来 5分钟带你体验kubernetes 对外提供访问

环境准备

本文是之前环境的延续。

kubernetes 对外提供访问

在master我们执行命令查看pod

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#  kubectl get pods -o wide
NAME                     READY   STATUS    RESTARTS   AGE   IP            NODE             NOMINATED NODE   READINESS GATES
myapp-799bbcd6b4-8nz5g   1/1     Running   0          91s   10.244.1.30   node01.k8s.com   <none>           <none>
myapp-799bbcd6b4-jms4x   1/1     Running   0          92s   10.244.1.29   node01.k8s.com   <none>           <none>
myapp-799bbcd6b4-l7q6v   1/1     Running   0          89s   10.244.2.34   node02.k8s.com   <none>           <none>

在master我们执行命令查看service

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查看 service
# kubectl get svc
NAME         TYPE        CLUSTER-IP      EXTERNAL-IP   PORT(S)   AGE
kubernetes   ClusterIP   10.96.0.1       <none>        443/TCP   72m
myapp        ClusterIP   10.100.210.72   <none>        80/TCP    17m

我们想要访问pod，目前只能在虚拟机的节点上访问，10.244.XXX.XXX的网址或者通过service服务的ip访问，
如果我们想要在虚拟机之外访问集群内部的地址，这个时候我们需要执行命令修改service的文件

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master上执行命令
# kubectl edit svc myapp

得到如下信息

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# Please edit the object below. Lines beginning with a '#' will be ignored,
# and an empty file will abort the edit. If an error occurs while saving this file will be
# reopened with the relevant failures.
#
apiVersion: v1
kind: Service
metadata:
  creationTimestamp: "2019-03-07T05:53:57Z"
  labels:
    run: myapp
  name: myapp
  namespace: default
  resourceVersion: "5195"
  selfLink: /api/v1/namespaces/default/services/myapp
  uid: 38910862-4942-11e9-bbc4-000c296cc22a
spec:
  clusterIP: 10.100.210.72
  ports:
  - port: 80
    protocol: TCP
    targetPort: 80
  selector:
    run: myapp
  sessionAffinity: None
  type: ClusterIP
status:
  loadBalancer: {}

找到 type: ClusterIP 修改为 type: NodePort
修改后结果

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# Please edit the object below. Lines beginning with a '#' will be ignored,
# and an empty file will abort the edit. If an error occurs while saving this file will be
# reopened with the relevant failures.
#
apiVersion: v1
kind: Service
metadata:
  creationTimestamp: "2019-03-18T05:53:57Z"
  labels:
    run: myapp
  name: myapp
  namespace: default
  resourceVersion: "5195"
  selfLink: /api/v1/namespaces/default/services/myapp
  uid: 38910862-4942-11e9-bbc4-000c296cc22a
spec:
  clusterIP: 10.100.210.72
  ports:
  - port: 80
    protocol: TCP
    targetPort: 80
  selector:
    run: myapp
  sessionAffinity: None
  type: NodePort
status:
  loadBalancer: {}

保存退出
再次查看service

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# kubectl get svc
NAME         TYPE        CLUSTER-IP      EXTERNAL-IP   PORT(S)        AGE
kubernetes   ClusterIP   10.96.0.1       <none>        443/TCP        4h14m
myapp        NodePort    10.100.210.72   <none>        80:32313/TCP   3h19m

发现myapp service的prot变为 80:32313/TCP，32313为master主机对外访问的端口号。
master的ip为 192.168.110.140，此时我们想要在虚拟机外部访问集群内部pod，需要使用 http://192.168.110.140:32313 。
在master节点上执行命令查看效果

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# curl http://192.168.110.140:32313
V1
myapp-799bbcd6b4-l7q6v
# curl http://192.168.110.140:32313
V1
myapp-799bbcd6b4-jms4x
# curl http://192.168.110.140:32313
V1
myapp-799bbcd6b4-8nz5g
# curl http://192.168.110.140:32313

同时我在虚拟机的外部机器上访问 http://192.168.110.140:32313

以上是kubernetes 对外提供访问 整个过程