Traefik配置后始终返回404，容器化Go应用无法访问

尝试为容器化Go应用配置Traefik，但所有端点访问均返回404。Go应用运行在my-service容器内，监听80端口，无Traefik时可正常运行，问题出在Traefik配置上。

docker-compose.yml #

version: '3'

services:

  my-service:
    container_name: my-service-backend
    labels:
      - traefik.http.routers.my-service.rule=Host(`my-service.docker.localhost`)
      - traefik.http.services.my-service.loadbalancer.server.port=80
      - traefik.port=80
      - traefik.enable=true
    build:
      context: .
      dockerfile: Dockerfile-${ENV}
    restart: always
    expose:
      - 80
    deploy:
      mode: replicated
      replicas: 1
    environment:
      USER: ${DB_USER}
      PASSWORD: ${DB_PASSWORD}
      DB: ${DB_NAME}
      HOST: ${DB_HOST}
      PORT: ${DB_PORT}
      LISTEN_PORT: ${LISTEN_PORT}
      ENV: ${ENV}
    networks:
      - backend
  
  traefik:
    image: traefik:v3.0
    # Enables the web UI and tells Traefik to listen to docker. DISABLE IN PRODUCTION
    command: --api.insecure=true --providers.docker
    ports:
      # The HTTP port
      - "80:80"
      # The Web UI (enabled by --api.insecure=true)
      - "8080:8080"
    volumes:
      # So that Traefik can listen to the Docker events
      - /var/run/docker.sock:/var/run/docker.sock
      - ./traefik.yaml:/etc/traefik/traefik.yaml
    networks:
      - backend

networks:
  backend:
    name: backend

traefik.yaml #

accessLog: {}
log: {}

providers:
  docker:
    exposedByDefault: false
    network: backend

api:
  dashboard: true
  insecure: true
  debug: true

entryPoints:
  web:
    address: ":80"
  websecure:
    address: ":443"

执行curl -GET localhost:80/ping和curl -GET my-service.docker.localhost/ping均返回404，Traefik日志显示：

192.168.65.1 - - [12/Jun/2024:03:51:12 +0000] "GET /ping HTTP/1.1" 404 19 "-" "-" 1 "my-service@docker" "http://172.18.0.3:80" 18ms

核心问题 #

1. 命令行与配置文件参数冲突：Traefik服务同时通过command和配置文件重复定义了API和Docker Provider参数，导致配置逻辑混乱。
2. 路由未绑定EntryPoint：Traefik v3要求路由必须明确关联到指定的EntryPoint，否则请求无法匹配到对应路由。
3. 冗余旧版本标签：traefik.port是Traefik v1的废弃标签，与v3的服务端口配置重复，易引发混淆。

修正步骤 #

1. 修复Traefik服务的启动命令

删除command中与配置文件重复的参数，改用配置文件统一管理：

traefik:
  image: traefik:v3.0
  command: --configfile=/etc/traefik/traefik.yaml
  ports:
    - "80:80"
    - "8080:8080"
  volumes:
    - /var/run/docker.sock:/var/run/docker.sock
    - ./traefik.yaml:/etc/traefik/traefik.yaml
  networks:
    - backend

2. 调整my-service的Traefik标签

添加EntryPoint绑定，删除废弃的traefik.port标签：

my-service:
  container_name: my-service-backend
  labels:
    - traefik.http.routers.my-service.rule=Host(`my-service.docker.localhost`)
    - traefik.http.routers.my-service.entrypoints=web  # 绑定到web入口点
    - traefik.http.services.my-service.loadbalancer.server.port=80
    - traefik.enable=true
  # 其余配置保持不变

3. 验证本地域名解析

确保本地hosts文件添加以下映射（避免域名解析失败）：

127.0.0.1 my-service.docker.localhost

验证操作 #

重启容器集群：

docker-compose down && docker-compose up -d

执行以下命令验证：

curl my-service.docker.localhost/ping

额外说明 #

• curl localhost:80/ping返回404是预期行为：路由规则仅匹配my-service.docker.localhost主机名，直接用localhost访问不匹配任何路由。
• 日志显示请求已转发到应用容器，说明Traefik已识别服务，修正后即可正常转发请求。

内容的提问来源于stack exchange，提问作者yulia