Spring Boot 3无法加载Kubernetes ConfigMap问题排查求助

我在EKS（Kubernetes 1.27）环境中部署了一个基于Spring Boot 3.1.1和Spring Cloud 2022.0.4的极简应用，但ConfigMap中的配置始终无法加载。

该应用仅包含一个文件，无本地application.yaml，用于提供static资源的内容：

package ch.brw.hive.frontend

import org.springframework.boot.autoconfigure.SpringBootApplication
import org.springframework.boot.runApplication

@SpringBootApplication
class App

fun main(args: Array<String>) {
    runApplication<App>(*args)
}

我的Gradle项目名为spring-boot-frontend，build.gradle.kts配置如下：

...
springBoot {
  buildInfo()
}
...
implementation("org.springframework.cloud:spring-cloud-starter-kubernetes-client")
implementation("org.springframework.cloud:spring-cloud-starter-kubernetes-client-config")
implementation("org.springframework.cloud:spring-cloud-starter-kubernetes-client-all")
...

我的deployment.yaml配置：

apiVersion: apps/v1
kind: Deployment
metadata:
  name: "spring-boot-frontend"
spec:
  replicas: 1
  strategy:
    type: RollingUpdate
  template:
    metadata:
      labels:
        app: "frontend"
    spec:
      containers:
        - name: "spring-boot-frontend"
          image: "{{ .Values.frontend.image.registry }}/{{ .Values.frontend.image.name }}:{{ .Values.frontend.image.tag }}"
          imagePullPolicy: {{ .Values.frontend.image.pullPolicy | quote }}
          ports:
            - name: http
              containerPort: 8080
          resources:
            {{- toYaml .Values.frontend.resources | nindent 12 }}
      restartPolicy: Always
  selector:
    matchLabels:
      app: "frontend"

我的configMap.yaml配置：

apiVersion: v1
kind: ConfigMap
metadata:
  name: "spring-boot-frontend"
data:
  application.yaml: |-
    server:
      port: 8181

我的role.yaml配置：

apiVersion: rbac.authorization.k8s.io/v1
kind: Role
metadata:
  name: {{ .Values.fullyQualifiedName }}
rules:
  - apiGroups: [""]
    resources: ["*"]
    verbs: ["*"]

我的roleBinding.yaml配置（使用默认ServiceAccount）：

apiVersion: rbac.authorization.k8s.io/v1
kind: RoleBinding
metadata:
  name: {{ .Values.fullyQualifiedName }}
subjects:
  - kind: ServiceAccount
    name: default
    namespace: {{ .Release.Namespace }}
roleRef:
  kind: Role
  name: {{ .Values.fullyQualifiedName }}
  apiGroup: ""

应用日志未显示任何错误：

.   ____          _            __ _ _
 /\ / ___'_ __ _ _(_)_ __  __ _ \ \ \ \
( ( )\___ | '_ | '_| | '_ \/ _` | \ \ \ \
 \/  ___)| |_)| | | | | || (_| |  ) ) ) )
  '  |____| .__|_| |_|_| |_\__, | / / / /
 =========|_|==============|___/=/_/_/_/
 :: Spring Boot ::                (v3.1.1)

2023-08-31T19:54:27.718Z  INFO 1 --- [           main] ch.brw.hive.frontend.AppKt               : Starting AppKt using Java 17.0.8 with PID 1 (/app/classes started by root in /)
2023-08-31T19:54:27.720Z  INFO 1 --- [           main] ch.brw.hive.frontend.AppKt               : The following 1 profile is active: "kubernetes"
2023-08-31T19:54:29.061Z  INFO 1 --- [           main] o.s.cloud.context.scope.GenericScope     : BeanFactory id=3d87bae4-72a0-3c9a-ad7b-c5d752a70bf4
2023-08-31T19:54:29.381Z  INFO 1 --- [           main] o.s.b.w.embedded.tomcat.TomcatWebServer  : Tomcat initialized with port(s): 8080 (http)
2023-08-31T19:54:29.391Z  INFO 1 --- [           main] o.apache.catalina.core.StandardService   : Starting service [Tomcat]
2023-08-31T19:54:29.392Z  INFO 1 --- [           main] o.apache.catalina.core.StandardEngine    : Starting Servlet engine: [Apache Tomcat/10.1.10]
2023-08-31T19:54:29.476Z  INFO 1 --- [           main] o.a.c.c.C.[Tomcat].[localhost].[/]       : Initializing Spring embedded WebApplicationContext
2023-08-31T19:54:29.479Z  INFO 1 --- [           main] w.s.c.ServletWebServerApplicationContext : Root WebApplicationContext: initialization completed in 1674 ms
2023-08-31T19:54:30.075Z  INFO 1 --- [           main] o.s.c.k.client.KubernetesClientUtils     : Created API client in the cluster.
2023-08-31T19:54:30.308Z  INFO 1 --- [ler-V1Endpoints] i.k.client.informer.cache.Controller     : informer#Controller: ready to run resync & reflector runnable
2023-08-31T19:54:30.308Z  INFO 1 --- [ler-V1Endpoints] i.k.client.informer.cache.Controller     : informer#Controller: resync skipped due to 0 full resync period
2023-08-31T19:54:30.310Z  INFO 1 --- [s.V1Endpoints-1] i.k.c.informer.cache.ReflectorRunnable   : class io.kubernetes.client.openapi.models.V1Endpoints#Start listing and watching...
2023-08-31T19:54:30.342Z  INFO 1 --- [els.V1Service-1] i.k.c.informer.cache.ReflectorRunnable   : class io.kubernetes.client.openapi.models.V1Service#Start listing and watching...
2023-08-31T19:54:31.308Z  INFO 1 --- [pool-9-thread-1] s.c.k.c.d.KubernetesDiscoveryClientUtils : Waiting for the cache of informers to be fully loaded..
2023-08-31T19:54:31.309Z  INFO 1 --- [           main] s.c.k.c.d.KubernetesDiscoveryClientUtils : Cache fully loaded (total 3 services), discovery client is now available
2023-08-31T19:54:31.464Z  INFO 1 --- [           main] o.s.b.a.e.web.EndpointLinksResolver      : Exposing 1 endpoint(s) beneath base path '/actuator'
2023-08-31T19:54:31.539Z  INFO 1 --- [           main] o.s.b.w.embedded.tomcat.TomcatWebServer  : Tomcat started on port(s): 8080 (http) with context path ''
2023-08-31T19:54:31.564Z  INFO 1 --- [           main] ch.brw.hive.frontend.AppKt               : Started AppKt in 4.674 seconds (process running for 5.105)

可以看到，Tomcat仍使用默认端口8080启动，并未加载ConfigMap中配置的8181端口。我反复查阅官方文档仍未找到原因，请问有人知道我遗漏了什么配置吗？

以下几个关键点可能是你遗漏的配置项：

• 明确开启Kubernetes Config加载
  Spring Cloud Kubernetes Client Config默认可能未自动启用ConfigMap加载，需要通过环境变量明确开启，并指定要匹配的ConfigMap名称。在Deployment的containers部分添加：

  env:
    - name: SPRING_CLOUD_KUBERNETES_CONFIG_ENABLED
      value: "true"
    - name: SPRING_CLOUD_KUBERNETES_CONFIG_NAME
      value: "spring-boot-frontend"
  

• 匹配激活的Profile
  日志显示应用激活的是kubernetes profile，而你的ConfigMap中是通用的application.yaml。可以修改ConfigMap的文件名，让配置对应到激活的profile：

  data:
    application-kubernetes.yaml: |-
      server:
        port: 8181
  

  或者通过环境变量强制导入ConfigMap配置：

  env:
    - name: SPRING_CONFIG_IMPORT
      value: "kubernetes:"
  

• 同步Deployment的容器端口
  即使应用内部端口改为8181，Deployment中的containerPort仍为8080会导致Kubernetes路由异常，需要同步修改：

  ports:
    - name: http
      containerPort: 8181
  

• 细化RBAC权限
  虽然你的Role配置了全量资源权限，但可以明确指定ConfigMap相关的权限，避免潜在的权限范围问题：

  rules:
    - apiGroups: [""]
      resources: ["configmaps"]
      verbs: ["get", "list", "watch"]
  

• 开启调试日志排查
  如果以上调整后仍未生效，添加调试日志查看配置加载的详细过程：

  env:
    - name: LOGGING_LEVEL_ORG_SPRINGFRAMEWORK_CLOUD_KUBERNETES
      value: "DEBUG"
    - name: LOGGING_LEVEL_ORG_SPRINGFRAMEWORK_BOOT_CONTEXT_CONFIG
      value: "DEBUG"
  

内容的提问来源于stack exchange，提问作者Geoffrey