Docker Compose启动微服务时服务连接被拒，但本地可访问的问题

本地通过浏览器或命令行启动Eureka服务时，可正常访问http://localhost:8888/eureka-server/docker，但执行docker-compose up启动时，Eureka服务抛出连接拒绝错误：

2024-04-13T15:45:36.659Z  INFO 1 --- [           main] c.c.c.ConfigServicePropertySourceLocator : Exception on Url - http://localhost:8888:org.springframework.web.client.ResourceAccessException: I/O error on GET request for "http://localhost:8888/eureka-server/docker": Connection refused.

相关配置文件如下：

Config Server的application.yml #

server:
  port: 8888

spring:
  cloud:
    config:
      server:
        git:
          uri: https://github.com/xyz/config-repo.git
          username: xyz
          password: xyz

# WARNING: Exposing all management endpoints over http should only be used during development, must be locked down in production!
# WARNING: Exposing all management endpoints over http should only be used during development, must be locked down in production!
management.endpoint.health.show-details: "ALWAYS"
management.endpoints.web.exposure.include: "*"

logging:
  level:
    root: info

---
spring:
  config:
    activate:
      on-profile: docker
  cloud:
    config:
      server:
        git:
          uri: https://github.com/xyz/config-repo.git
          username: xyz
          password: xyz

Eureka Server的application.yml #

spring.config.import: "configserver:http://localhost:8888"

spring:
  application.name: eureka-server
  cloud.config:
    failFast: true
    retry:
      initialInterval: 3000
      multiplier: 1.3
      maxInterval: 10000
      maxAttempts: 20
    uri: http://localhost:8888
    username: root
    password: root
management:
  security:
    enabled: false

---
spring.config.activate.on-profile: docker

spring.cloud.config.uri: http://config-server:8888

docker-compose.yml #

version: '2.1'

services:

  config-server:
    build: spring-cloud/config-server
    mem_limit: 512m
    networks:
      - my-network
    environment:
      - SPRING_PROFILES_ACTIVE=docker
      - ENCRYPT_KEY=my-very-secure-encrypt-key
      - SPRING_SECURITY_USER_NAME=root
      - SPRING_SECURITY_USER_PASSWORD=root
    volumes:
      - $PWD/config-repo:/config-repo
    ports:
      - "8888:8888"


  eureka:
    build: spring-cloud/eureka-server
    mem_limit: 512m
    networks:
      - my-network
    environment:
      - SPRING_PROFILES_ACTIVE=docker
      - ENCRYPT_KEY=my-very-secure-encrypt-key
      - CONFIG_SERVER_USR=root
      - CONFIG_SERVER_PWD=root
    ports:
      - "8761:8761"

networks:
  my-network:
    name: my-network

问题根源 #

Docker容器内的localhost指向容器自身而非宿主机。虽然你在Docker Profile中配置了spring.cloud.config.uri: http://config-server:8888，但spring.config.import的配置未被覆盖，导致Eureka仍尝试访问容器内的localhost:8888，而容器内未运行Config Server，因此出现连接拒绝。

修复步骤 #

1. 更新Eureka的application.yml，在Docker Profile中同时覆盖spring.config.import配置：

---
spring.config.activate.on-profile: docker

spring.config.import: "configserver:http://config-server:8888"
spring.cloud.config.uri: http://config-server:8888

2. 配置服务启动依赖与健康检查，确保Config Server就绪后再启动Eureka：

   • 修改docker-compose.yml中config-server服务，添加健康检查：

   config-server:
     build: spring-cloud/config-server
     mem_limit: 512m
     networks:
       - my-network
     environment:
       - SPRING_PROFILES_ACTIVE=docker
       - ENCRYPT_KEY=my-very-secure-encrypt-key
       - SPRING_SECURITY_USER_NAME=root
       - SPRING_SECURITY_USER_PASSWORD=root
     volumes:
       - $PWD/config-repo:/config-repo
     ports:
       - "8888:8888"
     healthcheck:
       test: ["CMD", "curl", "-f", "http://root:root@localhost:8888/actuator/health"]
       interval: 5s
       timeout: 5s
       retries: 5
   

   • 修改eureka服务，添加依赖条件：

   eureka:
     build: spring-cloud/eureka-server
     mem_limit: 512m
     networks:
       - my-network
     environment:
       - SPRING_PROFILES_ACTIVE=docker
       - ENCRYPT_KEY=my-very-secure-encrypt-key
       - CONFIG_SERVER_USR=root
       - CONFIG_SERVER_PWD=root
     ports:
       - "8761:8761"
     depends_on:
       config-server:
         condition: service_healthy
   

3. 验证修复：执行docker-compose down && docker-compose up，此时Eureka会通过Docker内部DNS解析config-server服务，正常连接到Config Server。

内容的提问来源于stack exchange，提问作者MAYANK DEVRANI