我有遗留的PHP应用程序.它使用mysqli来制作mysql的东西.所以在配置中我有DSN字符串连接到mysql服务.像那样

MySQL的：//用户名：密码@ db_hostname / DBNAME

Mysqli返回错误

警告：mysqli :: real_connect()：php_network_getaddresses：getaddrinfo failed：名称或服务未知

但是,如果我尝试使用此手动连接

mysqli的:: real_connect( “db_hostname”)

它说警告：mysqli :: real_connect():( HY000 / 1045)：用户”’172.21.0.3’拒绝访问(使用密码：否)

real_connect(“user @ db_hostname”),real_connect(“mysql：db_hostname”),real_connect(“mysql：host = db_hostname”)无法解析主机地址.

我做错了什么？

泊坞窗,compose.yml：

version: "3"
services:
  nginx:
    image: nginx:1.13-alpine
    volumes:
      - ./docker/nginx/nginx.conf:/etc/nginx/conf.d/default.conf:ro
      - ./docker/nginx/errors.log:/var/logs/errors.log
      - ./docker/nginx/access.log:/var/logs/access.log
      - ./:/var/www/html
    ports:
      - "8081:80"
    command: nginx -g "daemon off;"
  php:
    build:
      context: ./docker/
      dockerfile: php.Dockerfile
    user: "1000"
    volumes:
      - ./docker/timezone.php.ini:/usr/local/etc/php/conf.d/timezone.php.ini:ro
      - /etc/timezone:/etc/timezone:ro
      - /etc/localtime:/etc/localtime:ro
      - ./:/var/www/html

  db_hostname:
    image: mysql:5.5
    user: "1000"
    environment:
      - MYSQL_DATABASE=db
      - MYSQL_ROOT_PASSWORD=root
      - MYSQL_USER=user
      - MYSQL_PASSWORD=user
    volumes:
      - ./docker/mysql:/var/lib/mysql
      - /etc/timezone:/etc/timezone:ro
      - /etc/localtime:/etc/localtime:ro

解决方法:

因为你错过了将db容器与php连接起来.当您将db与PHP链接时,可以从PHP的localhost访问它.

这是我修改你的docker-compose文件,因为我喜欢高山到处都是;).我使用adminer并与db链接到verfiy连接而不是代码级别检查.因为我没有你的php docker文件所以我正在创建php：alpine其中包含php7.

version: "3"
services:
  nginx:
    image: nginx:1.13-alpine
    container_name: nginx
    ports:
      - "8081:80"
    command: nginx -g "daemon off;"
  db:
    image: mysql:5.5
    environment:
      MYSQL_ROOT_PASSWORD: example

  php:
    image: php:alpine
    container_name: php
    tty: true
    links:
     - db 
  adminer:
    image: adminer
    container_name: adminer
    ports:
      - 8080:8080
    links:
     - db 

然后我在php容器中安装了mysqli

docker exec -it php ash

并在命令下运行

docker-php-ext-install mysqli;

然后创建test.php

这里服务器名称是db.请注意,您的服务器名称将是链接到php的db容器名称.
如果你在php容器中ping db,它将ping数据库容器.

    <?php
$servername = "db";
$username = "root";
$password = "example";

// Create connection
$conn = new mysqli($servername, $username, $password);

// Check connection
if ($conn->connect_error) {
    die("Connection failed: " . $conn->connect_error);
} 
echo "Connected successfully";
?>

现在在php容器中运行此文件.您可以挂载并运行您的PHP代码,但这是我为测试所做的.我作为root用户尝试过.

php -f test.php

这里是与db连接的adminer