Docker-Nginx：在上游找不到主机

Question

我下载了官方Docker软件包，然后设置了docker-compose。一切都可以编译，但是如果我将docker-compose up，则会收到以下错误消息：

project-websrv | 2017/09/22 10:18:35 [emerg] 1#1: host not found in upstream "php-fpm" in /etc/nginx/conf.d/default.conf:25
project-websrv | nginx: [emerg] host not found in upstream "php-fpm" in /etc/nginx/conf.d/default.conf:25
project-php exited with code 0

nginx.conf第25行：

fastcgi_pass php-fpm:9000;

我的docker-compose.yml

version: "3.1"
services:

    mysql:
      image: mariadb
      container_name: project-mariadb
      environment:
        MYSQL_ROOT_PASSWORD: root

    phpmyadmin:
      image: phpmyadmin/phpmyadmin
      container_name: project-pma
      restart: always
      links:
        - mysql
      ports:
        - 8183:80
      environment:
        PMA_HOST: mysql
        PMA_USER: root
        PMA_PASSWORD: root

    php-fpm:
      build: php
      container_name: project-php
      working_dir: /var/www/project
      volumes:
        - ../../Sources/project/trunk/src/:/var/www/project
        - ./php/php-ini-overrides.ini:/etc/php/7.0/fpm/conf.d/99-overrides.ini
      links:
        - mysql      

    webserver:
      image: nginx
      container_name: project-websrv
      working_dir: /var/www/project
      volumes:
          - ../../Sources/project/trunk/src/:/var/www/project
          - ./nginx/nginx.conf:/etc/nginx/conf.d/default.conf  
      ports:
       - "8080:80"
      links:
       - php-fpm

资料夹结构：

php/
 - Dockerfile
 - php-ini-overrides.ini
mysql/
nginx/
 - nginx.conf
*docker-compose.yml

完整的nginx.conf

server {
    listen 80 default;

    client_max_body_size 108M;

    access_log /var/log/nginx/application.access.log;

    root /var/www/project/web;
    index app_dev.php;

    rewrite ^/app\.php/?(.*)$ /$1 permanent;

    try_files $uri @rewriteapp;

    location @rewriteapp {
        rewrite ^(.*)$ /app_dev.php/$1 last;
    }

    # Deny all . files
    location ~ /\. {
        deny all;
    }

    location ~ ^/(app|app_dev)\.php(/|$) {
        fastcgi_pass php-fpm:9000;
        fastcgi_split_path_info ^(.+\.php)(/.*)$;
        fastcgi_index app.php;
        send_timeout 1800;
        fastcgi_read_timeout 1800;
        fastcgi_param  SCRIPT_FILENAME $document_root$fastcgi_script_name;
        fastcgi_param PHP_VALUE "error_log=/var/log/nginx/application_php_errors.log";
        fastcgi_buffers 16 16k;
        fastcgi_buffer_size 32k;
        include fastcgi_params;
    }

    # Statics
        location /(bundles|media) {
        access_log off;
        expires 30d;
        try_files $uri @rewriteapp;
    }
}

我检查URL两次，一切似乎正常，设置了nginx.conf并将其存储在此URL中。我在另一个容器中使用了相同的配置，但没有phpmyadmin和mariadb，它运行良好。