Nginx未转发请求至本地实例问题排查求助

访问localhost:8080/时页面显示Nginx默认页，无法转发至后端Go实例；访问localhost:8080/hello返回404错误，但直接访问localhost:5000/hello或localhost:5001/hello可正常显示"Hello World"。

当前配置 #

docker-compose.yml #

version: '3'
services:
  golang-instance:
    image: "myapi"
    ports:
      - "5000:5000"
    networks:
      - nginx_net
    restart: on-failure

  golang-instance-2:
    image: "myapi"
    ports:
      - "5001:5000"
    networks:
      - nginx_net
    restart: on-failure

  nginx:
    image: nginx
    ports:
      - "8080:80"
    volumes:
      - ./nginx.conf:/etc/nginx/conf.d/nginx.conf
    networks:
      - nginx_net
    restart: on-failure

networks:
  nginx_net:

nginx.conf #

upstream backend {
    least_conn;
    server golang-instance:5000;
    server golang-instance-2:5000;
}

server {
    listen 80;
    server_name localhost;

    location / {
        proxy_pass http://backend;
    }
}

错误日志 #

访问localhost:8080/hello时，Nginx容器日志：

2023-09-30T18:32:28.873946632Z 172.20.0.1 - - [30/Sep/2023:18:32:28 +0000] "GET /hello HTTP/1.1" 404 555 "-" "Mozilla/5.0 (Macintosh; Intel Mac OS X 10_15_7) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/114.0.0.0 Safari/537.36" "-"

已尝试的操作 #

• 移除least_conn配置，无效果
• 修改Nginx的listen端口为8080，无效果
• 调整golang-instance-2的端口映射为5001，无效果
• 将网络改为bridge驱动，未解决问题
• 尝试三种volume映射方式：
  1. 映射到/etc/nginx/nginx.conf：容器可启动，但问题依旧
  2. 映射到/etc/nginx/conf.d/nginx.conf：容器可启动，但问题依旧
  3. 映射到/etc/nginx/http.d/nginx.conf：容器启动失败，报错"upstream" directive is not allowed here

容器启动日志（option-1和option-2）：

/docker-entrypoint.sh: /docker-entrypoint.d/ is not empty, will attempt to perform configuration 2023-09-30T17:40:27.718888715Z /docker-entrypoint.sh: Looking for shell scripts in /docker-entrypoint.d/ 2023-09-30T17:40:27.720393590Z /docker-entrypoint.sh: Launching /docker-entrypoint.d/10-listen-on-ipv6-by-default.sh 2023-09-30T17:40:27.724760049Z 10-listen-on-ipv6-by-default.sh: info: IPv6 listen already enabled 2023-09-30T17:40:27.724773299Z /docker-entrypoint.sh: Sourcing /docker-entrypoint.d/15-local-resolvers.envsh 2023-09-30T17:40:27.725033174Z /docker-entrypoint.sh: Launching /docker-entrypoint.d/20-envsubst-on-templates.sh 2023-09-30T17:40:27.731775465Z /docker-entrypoint.sh: Launching /docker-entrypoint.d/30-tune-worker-processes.sh 2023-09-30T17:40:27.736814424Z /docker-entrypoint.sh: Configuration complete; ready for start up 2023-09-30T17:40:27.759872299Z 2023/09/30 17:40:27 [warn] 1#1: conflicting server name "localhost" on 0.0.0.0:80, ignored 2023-09-30T17:40:27.759900590Z nginx: [warn] conflicting server name "localhost" on 0.0.0.0:80, ignored 2023-09-30T17:40:27.760202507Z 2023/09/30 17:40:27 [notice] 1#1: using the "epoll" event method 2023-09-30T17:40:27.760207549Z 2023/09/30 17:40:27 [notice] 1#1: nginx/1.25.2 2023-09-30T17:40:27.760209590Z 2023/09/30 17:40:27 [notice] 1#1: built by gcc 12.2.0 (Debian 12.2.0-14) 2023-09-30T17:40:27.760211382Z 2023/09/30 17:40:27 [notice] 1#1: OS: Linux 5.15.49-linuxkit 2023-09-30T17:40:27.760213090Z 2023/09/30 17:40:27 [notice] 1#1: getrlimit(RLIMIT_NOFILE): 1048576:1048576 2023-09-30T17:40:27.761007132Z 2023/09/30 17:40:27 [notice] 1#1: start worker processes 2023-09-30T17:40:27.761015632Z 2023/09/30 17:40:27 [notice] 1#1: start worker process 22 2023-09-30T17:40:27.764749424Z 2023/09/30 17:40:27 [notice] 1#1: start worker process 23 2023-09-30T17:40:27.764774007Z 2023/09/30 17:40:27 [notice] 1#1: start worker process 24 2023-09-30T17:40:27.764776340Z 2023/09/30 17:40:27 [notice] 1#1: start worker process 25

排查建议 #

• 清理Nginx默认配置：官方Nginx镜像默认加载/etc/nginx/conf.d/default.conf，该配置包含默认页的server块。进入Nginx容器删除此文件后重启：

  docker exec -it <nginx-container-id> rm /etc/nginx/conf.d/default.conf
  docker restart <nginx-container-id>
  

• 验证生效配置：进入容器执行nginx -T，查看完整生效配置，确认自定义server块是否存在且优先级正确。
• 调整代理配置：修改proxy_pass为http://backend/（添加尾部斜杠），或添加proxy_set_header Host $host;，确保请求路径和头部正确传递到后端。
• 测试容器间连通性：在Nginx容器内执行ping golang-instance验证DNS解析，再用curl http://golang-instance:5000/hello测试后端服务是否可访问。
• 开启调试日志：在Nginx配置中添加error_log /var/log/nginx/error.log debug;，重启后查看详细日志定位转发失败原因。

内容的提问来源于stack exchange，提问作者Arthur