Nginx Ingress Controller返回404，请求排查K8s配置问题

我在WSL2的minikube环境中为Kubernetes Service配置Ingress，Service直接访问正常，但通过Ingress访问返回404。以下是我的配置和测试过程：

Deployment配置 #

apiVersion: apps/v1
kind: Deployment
metadata:
    name: {{.Chart.Name}}-backend
    labels:
        app: {{.Chart.Name}}-backend
spec:
    replicas: {{ .Values.replicas }}
    selector:
        matchLabels:
            service: backend
            app: {{.Chart.Name}}-backend
    template:
        metadata:
            labels:
                service: backend
                app: {{.Chart.Name}}-backend
        spec:  
            containers:
            -   name: kuberdemo-app
                image: {{ .Values.image }}
                ports:
                -   containerPort: 8091
                    targetPort: 8091
                    protocol: TCP
                    name: app-port
                envFrom:
                - configMapRef:
                    name: kuberdemo-config
                startupProbe:
                    httpGet:
                        path: /actuator/health/liveness
                        port: 14000
                    failureTreshold: 2
                    periodSeconds: 10
                readinessProbe:
                    httpGet:
                        path: /actuator/health/readiness
                        port: 14000
                    failureTreshold: 2
                    periodSeconds: 10
                livenessProbe:
                    httpGet:
                        path: /actuator/health/liveness
                        port: 14000
                    failureTreshold: 2
                    periodSeconds: 10
                resources:
                    limits:
                        cpu: "2000m"
                        memory: "2Gi"
                    requests:
                        cpu: "2000m"
                        memory: "2Gi"

Service配置 #

apiVersion: v1
kind: Service
metadata:
  name: kuberdemo-service
spec:
  type: ClusterIP
  selector:
    app: {{.Chart.Name}}-backend
  ports:
    - protocol: TCP
      port: 8090
      targetPort: 8091

Ingress配置 #

apiVersion: networking.k8s.io/v1
kind: Ingress
metadata:
  name: kuberdemo-ingress
spec:
  rules:
    - host: kuberdemo.info
      http:
        paths:
          - path: /
            pathType: Prefix
            backend:
              service:
                name: kuberdemo-service
                port:
                  number: 8090

测试情况 #

• Service直接转发正常：
  执行命令：

  kubectl port-forward service/kuberdemo-service -n kuberdemo 8080:8090
  curl --location 'http://localhost:8080/users'
  

  返回[]（数据库无数据，符合预期）。

• 通过Ingress Controller转发返回404：
  执行命令：

  kubectl port-forward -n ingress-nginx ingress-nginx-controller-6cc5ccb977-zzbcb 8080:80
  curl --location 'http://localhost:8080/users'
  

  返回NGINX的404页面：

  <html>
  <head><title>404 Not Found</title></head>
  <body>
  <center><h1>404 Not Found</h1></center>
  <hr><center>nginx</center>
  </body>
  </html>
  

问题原因及修复方案 #

• 核心问题：Ingress规则中指定了host: kuberdemo.info，但测试时直接用localhost访问，NGINX找不到匹配的Ingress规则，因此返回404。

• 修复方式三选一即可：

  1. 添加本地hosts映射：
     在Windows主机的C:\Windows\System32\drivers\etc\hosts（或WSL2内部的/etc/hosts）中添加一行：

     127.0.0.1 kuberdemo.info
     

     之后直接用域名访问：

     curl --location 'http://kuberdemo.info:8080/users'
     

  2. curl请求指定Host头：
     无需修改hosts，直接在curl命令中指定Host头匹配Ingress规则：

     curl --location 'http://localhost:8080/users' --header 'Host: kuberdemo.info'
     

  3. 移除Ingress的host限制：
     如果不需要域名匹配，删除Ingress配置中的host: kuberdemo.info，这样所有发往Ingress的请求都会匹配该规则。修改后的Ingress配置：

     apiVersion: networking.k8s.io/v1
     kind: Ingress
     metadata:
       name: kuberdemo-ingress
     spec:
       rules:
         - http:
             paths:
               - path: /
                 pathType: Prefix
                 backend:
                   service:
                     name: kuberdemo-service
                     port:
                       number: 8090
     

内容的提问来源于stack exchange，提问作者SkyWaet