Kubernetes服务DNS无法访问

Question

我正处于学习Kubernetes的阶段，试图创建一个服务并通过ping / curl访问它。

Step1:在默认命名空间中创建部署mytomcat

alias k='kubectl'
k create deployment mytomcat --image=tomcat

Step2:在默认命名空间中创建了一个带curl的部署busybox

apiVersion: v1
kind: Pod
metadata:
  name: mybusybox
  namespace: default
spec:
  containers:
  - image: yauritux/busybox-curl
    command:
      - sleep
      - "3600"
    imagePullPolicy: IfNotPresent
    name: busybox
  restartPolicy: Always

k apply -f busybox.yaml
k exec mybusybox -t -i -- sh

Step3:对mytomcat pod执行Ping操作，可以正常工作

ping 10.1.1.11
PING 10.1.1.11 (10.1.1.11): 56 data bytes
64 bytes from 10.1.1.11: seq=0 ttl=64 time=0.207 ms

Step4:创建一个服务来公开tomcat上的8080端口

k expose deployment mytomcat --port=8080 

Step5:获取所有资源的统计信息

k get all -o wide
NAME                            READY   STATUS    RESTARTS   AGE   IP          NODE             NOMINATED NODE   READINESS GATES
pod/mybusybox                   1/1     Running   0          10m   10.1.1.14   docker-desktop   <none>           <none>
pod/mytomcat-6bfbf4c889-xqkg9   1/1     Running   0          39m   10.1.1.11   docker-desktop   <none>           <none>

NAME                 TYPE        CLUSTER-IP      EXTERNAL-IP   PORT(S)    AGE     SELECTOR
service/kubernetes   ClusterIP   10.96.0.1       <none>        443/TCP    42m     <none>
service/mytomcat     ClusterIP   10.102.120.90   <none>        8080/TCP   6m40s   app=mytomcat

NAME                       READY   UP-TO-DATE   AVAILABLE   AGE   CONTAINERS   IMAGES   SELECTOR
deployment.apps/mytomcat   1/1     1            1           39m   tomcat       tomcat   app=mytomcat

NAME                                  DESIRED   CURRENT   READY   AGE   CONTAINERS   IMAGES   SELECTOR
replicaset.apps/mytomcat-6bfbf4c889   1         1         1       39m   tomcat       tomcat   app=mytomcat,pod-template-hash=6bfbf4c889

Step7:卷曲服务到达tomcat pod失败。这是预期的输出吗？因为它说的是错误代码404。我不知道tomcat服务器是如何工作的。

    curl http://mytomcat:8080
<!doctype html><html lang="en"><head><title>HTTP Status 404 – Not Found</title><style type="text/css">body {font-family:Tahoma,Arial,sans-serif;} h1, h2, h3, b {color:white;background-color:#525D76;} h1 {font-size:22px;} h2 {font-size:16px;} h3 {font-size:14px;} p {font-size:12px;} a {color:black;} .line {height:1px;background-color:#525D76;border:none;}</style></head><body><h1>HTTP Status 404 – Not Found</h1><hr class="line" /><p><b>Type</b> Status Report</p><p><b>Description</b> The origin server did not find a current representation for the target resource or is not willing to disclose that one exists.</p><hr class="line" /><h3>Apache Tomcat/9.0.37</h3></body></html>/home

有没有人可以建议我在哪里做错了，或者从一开始就建议好的学习资源。

谢谢。

Answer 1

这根本不是DNS Unreachable问题或DNS问题。这是意料之中的，因为您还没有在tomcat上部署war文件，因此使用HTTP Status 404 – Not Found

请参考此问题，了解如何在kubernetes中运行的tomcat上部署war文件。Deploy WAR in Tomcat on Kubernetes