部署Spring Boot到Minikube后无法访问REST端点的解决方法

我有一个Spring Boot Web应用，已Docker化，希望通过Minikube部署到本地Kubernetes集群并访问其REST端点。

相关代码与配置 #

REST API代码 #

@RestController
public class SampleController {

    @RequestMapping("/x")
    public String example(){
        return "hello world";
    }
}

Dockerfile #

FROM eclipse-temurin:17
ARG JAR_FILE=target/k8s-example-0.0.1-SNAPSHOT.jar
ADD ${JAR_FILE} app.jar
ENTRYPOINT ["java", "-jar", "app.jar"]

docker-compose.yml #

version: '3.1'
services:
  app:
    container_name: first-docker-container
    restart: always
    image: first-docker-image
    build: ./
    ports:
      - "8082:8080"

执行docker build -t first-docker-image .和docker-compose up后，可正常通过localhost:8082/x访问端点。

Kubernetes Deployment配置（deployment.yml） #

apiVersion: apps/v1
kind: Deployment
metadata:
  name: first-kubernetes-example
spec:
  selector:
    matchLabels:
      app: first-kubernetes-example
  replicas: 1
  template:
    metadata:
      labels:
        app: first-kubernetes-example
    spec:
      containers:
        - name: first-kubernetes-example
          image: first-docker-image
          imagePullPolicy: IfNotPresent
          ports:
            - containerPort: 8082

Kubernetes Service配置（service.yml） #

apiVersion: v1
kind: Service
metadata:
  name: my-service-with-nodeport
spec:
  type: NodePort
  ports:
    - port: 9090
      targetPort: 8082
      nodePort: 30008
      protocol: "TCP"
  selector:
    app: first-kubernetes-example

执行kubectl apply -f deployment.yml和kubectl apply -f service.yml后，应用已成功部署到Kubernetes Pod。kubectl get services输出如下：

NAME                       TYPE        CLUSTER-IP      EXTERNAL-IP   PORT(S)          AGE
kubernetes                 ClusterIP   10.96.0.1       <none>        443/TCP          122m
my-service-with-nodeport   NodePort    10.104.11.180   <none>        9090:30008/TCP   121m

Minikube IP为192.168.59.2，但无法通过192.168.59.2:30008/x访问端点，不想使用端口转发，求解决方案。

问题核心是容器端口配置不匹配，修复步骤如下：

1. 明确端口对应关系
   Spring Boot应用默认监听8080端口，Dockerfile未修改端口配置，容器内应用实际运行在8080端口。docker-compose的8082:8080只是宿主机到容器的端口映射，但Kubernetes配置里错误地将containerPort和targetPort设为了8082，导致服务无法正确路由到容器内的应用端口。

2. 修正Kubernetes配置

   • 更新deployment.yml，将容器端口改为8080：

     apiVersion: apps/v1
     kind: Deployment
     metadata:
       name: first-kubernetes-example
     spec:
       selector:
         matchLabels:
           app: first-kubernetes-example
       replicas: 1
       template:
         metadata:
           labels:
             app: first-kubernetes-example
         spec:
           containers:
             - name: first-kubernetes-example
               image: first-docker-image
               imagePullPolicy: IfNotPresent
               ports:
                 - containerPort: 8080  # 修正为应用实际监听的端口
     

   • 更新service.yml，将targetPort改为8080：

     apiVersion: v1
     kind: Service
     metadata:
       name: my-service-with-nodeport
     spec:
       type: NodePort
       ports:
         - port: 9090
           targetPort: 8080  # 修正为容器内应用的端口
           nodePort: 30008
           protocol: "TCP"
       selector:
         app: first-kubernetes-example
     

3. 重新部署配置
   执行命令更新部署：

   kubectl apply -f deployment.yml
   kubectl apply -f service.yml
   

4. 额外验证点
   若Pod启动异常，检查Minikube是否能访问本地构建的镜像：执行eval $(minikube docker-env)切换到Minikube的Docker环境，重新构建镜像docker build -t first-docker-image .，确保Kubernetes能拉取到镜像。

等待Pod重启完成后，访问192.168.59.2:30008/x即可获取"hello world"响应。

内容的提问来源于stack exchange，提问作者EMRE BİNNAZ