MiniKube ExternalName服务无法访问本地资源问题排查求助

已查阅资源（一周未解决） #

• StackOverflow上所有ExternalName访问相关问题
• Kubernetes ExternalName官方文档
• 多个关于ExternalName的YouTube视频
• 多个Kubernetes网络相关YouTube视频
• Medium上关于Pod访问外部数据库的文章

环境与问题详情 #

本地环境配置 #

• 本地机器运行Docker容器nginx，使用nginx:stable-perl镜像，端口映射为8090，Chrome访问http://192.168.56.1:8090可正常显示"Welcome to nginx!"页面，192.168.56.1为本地机器IP。
• 本地通过minikube start --driver=hyperv启动Minikube，其中运行helloworld Pod，镜像为bhargavshah86/kube-test:v0.1：

PS C:\data\code\unleash> kubectl get pods
NAME                          READY   STATUS    RESTARTS   AGE
helloworld-8654c996c4-thjrf   1/1     Running   0          9m48s

• 执行过端口转发命令：

kubectl --namespace default port-forward helloworld-8654c996c4-thjrf 8090:8090

• 本地etc\hosts配置：

192.168.56.1 my.web

Pod内测试结果 #

• nslookup执行结果（注：命令格式有误，误将端口作为DNS服务器参数，但解析到了目标IP）：

/usr/share/nginx/html # nslookup 192.168.56.1 8090
Server:    0.0.31.154
Address 1: 0.0.31.154

Name:      192.168.56.1
Address 1: 192.168.56.1 my.web

• curl本地IP超时（注：命令格式有误，多空格导致访问80端口而非8090）：

/usr/share/nginx/html # curl 192.168.56.1 8090
curl: (7) Failed to connect to 192.168.56.1 port 80: Operation timed out

• curlExternalName服务my-web无法解析主机：

/usr/share/nginx/html # curl http://my-web:8090
curl: (6) Could not resolve host: my-web

• 使用服务完整域名访问同样失败：

/usr/share/nginx/html # curl my-web.default.svc.cluster.local:8090
curl: (6) Could not resolve host: my-web.default.svc.cluster.local

• telnet连接超时：

/usr/share/nginx/html # busybox-extras telnet 192.168.56.1 8090
telnet: can't connect to remote host (192.168.56.1): Operation timed out

• 安装postgresql-client后访问本地Postgres（192.168.56.1:5432）报错：

psql -h 192.168.56.1 -U postgres

• Pod内curl www.google.com可正常访问。

相关资源配置 #

my-web服务描述 #

PS C:\data\code\unleash> kubectl describe svc/my-web
Name:              my-web
Namespace:         default
Labels:            <none>
Annotations:       <none>
Selector:          <none>
Type:              ExternalName
IP Families:       <none>
IP:
IPs:               <none>
External Name:     192.168.56.1
Port:              <unset>  8090/TCP
TargetPort:        8090/TCP
Endpoints:         <none>
Session Affinity:  None
Events:            <none>

minikube tunnel执行报错 #

PS C:\data\code\unleash> minikube tunnel --bind-address=192.168.56.1
W0424 19:34:25.670477   20364 main.go:291] Unable to resolve the current Docker CLI context "default": context "default": context not found: open C:\Users\srhusain\.docker\contexts\meta\37a8eec1ce19687d132fe29051dca629d164e2c4958ba141d5f4133a33f0688f\meta.json: The system cannot find the path specified.
E0424 19:34:29.903003   20364 out.go:453] unable to execute error getting ssh port: get port 22 for "minikube": hyperv container inspect -f "'{{(index (index .NetworkSettings.Ports \"22/tcp\") 0).HostPort}}'" minikube: exec: "hyperv": executable file not found in %PATH%
stdout:

stderr:
: template: error getting ssh port: get port 22 for "minikube": hyperv container inspect -f "'{{(index (index .NetworkSettings.Ports \"22/tcp\") 0).HostPort}}'" minikube: exec: "hyperv": executable file not found in %!P(string=index)ATH&{%!
(string=index of untyped nil)}stdout:

stderr:
:1:92: executing "error getting ssh port: get port 22 for \"minikube\": hyperv container inspect -f \"'{{(index (index .NetworkSettings.Ports \"22/tcp\") 0).HostPort}}'\" minikube: exec: \"hyperv\": executable file not found in %PATH%\nstdout:\n\nstderr:\n" at <index .NetworkSettings.Ports "22/tcp">: error calling %!s(MISSING): 
%!w(MISSING) - returning raw string.

❌  Exiting due to DRV_PORT_FORWARD: error getting ssh port: get port 22 for "minikube": hyperv container inspect -f "'{{(index (index .NetworkSettings.Ports \"22/tcp\"
) 0).HostPort}}'" minikube: exec: "hyperv": executable file not found in %PATH%
stdout:

stderr:


╭─────────────────────────────────────────────────────────────────────────────────────────────────────────────╮
│                                                                                                             │
│    😿  If the above advice does not help, please let us know:                                               │
│    👉  https://github.com/kubernetes/minikube/issues/new/choose                                             │
│                                                                                                             │
│    Please run `minikube logs --file=logs.txt` and attach logs.txt to the GitHub issue.                      │
│    Please also attach the following file to the GitHub issue:                                               │
│    - C:\Users\srhusain\AppData\Local\Temp\minikube_tunnel_df9325734b3fbaf9471c9c4a9cc1524d4e32b11a_0.log    │
│                                                                                                             │
╰─────────────────────────────────────────────────────────────────────────────────────────────────────────────╯

已尝试的ExternalName配置修改 #

spec:
  type: ExternalName
  externalName: my.web
# ---
spec:
  type: ExternalName
  externalName: 192.168.56.1

完整YAML配置 #

apiVersion: apps/v1
kind: Deployment
metadata:
  name: helloworld
  labels:
    app: helloworld
spec:
  replicas: 1
  selector:
    matchLabels:
      app: helloworld
  template:
    metadata:
      labels:
        app: helloworld
    spec:
      containers:
      - name: helloworld
        image:  bhargavshah86/kube-test:v0.1
        resources:
          limits:
            memory: 512Mi
            cpu: "1"
          requests:
            memory: 256Mi
            cpu: "0.2"
        ports:
        - containerPort: 8080

---
apiVersion: v1
kind: Service
metadata:
  name: my-web
spec:
  type: ExternalName
  externalName: 192.168.56.1
  ports:
  - port: 8090
    protocol: TCP
    targetPort: 8090

Endpoints信息 #

PS C:\data\code\unleash> kubectl get endpoints
NAME         ENDPOINTS             AGE
helloworld   10.244.0.11:8080      3h4m
kubernetes   172.18.112.240:8443   4h3m

Pod信息 #

PS C:\data\code\unleash> kubectl get pods -o wide
NAME                          READY   STATUS    RESTARTS   AGE   IP            NODE       NOMINATED NODE   READINESS GATES
helloworld-8654c996c4-mm4m2   1/1     Running   0          20m   10.244.0.11   minikube   <none>           <none>

期望结果 #

Pod内执行curl http://192.168.56.1:8090或curl http://my-web:8090能正常返回"Welcome to nginx!"页面，而非超时或解析失败。

内容的提问来源于stack exchange，提问作者Syed Rafey Husain