Laravel+Docker多库迁移：第二个MariaDB数据库连接超时故障

环境配置 #

.env 文件配置 #

DB_CONNECTION=mysql
DB_HOST=10.0.0.4
DB_PORT=3306
DB_DATABASE=x
DB_USERNAME=root
DB_PASSWORD=

DB_CONNECTION_SECOND=mysql_second
DB_HOST_SECOND=10.0.0.4
DB_PORT_SECOND=3307
DB_DATABASE_SECOND=y
DB_USERNAME_SECOND=root
DB_PASSWORD_SECOND=

database.php 配置 #

'mysql' => [
    'driver' => 'mysql',
    'url' => env('DB_URL'),
    'host' => env('DB_HOST', '127.0.0.1'),
    'port' => env('DB_PORT', '3306'),
    'database' => env('DB_DATABASE', 'laravel'),
    'username' => env('DB_USERNAME', 'root'),
    'password' => env('DB_PASSWORD', ''),
    'unix_socket' => env('DB_SOCKET', ''),
    'charset' => env('DB_CHARSET', 'utf8mb4'),
    'collation' => env('DB_COLLATION', 'utf8mb4_unicode_ci'),
    'prefix' => '',
    'prefix_indexes' => true,
    'strict' => true,
    'engine' => null,
    'options' => extension_loaded('pdo_mysql') ? array_filter([
        PDO::MYSQL_ATTR_SSL_CA => env('MYSQL_ATTR_SSL_CA'),
    ]) : [],
],

'mysql_second' => [
    'driver' => 'mysql',
    'host' => env('DB_HOST_SECOND', '127.0.0.1'),
    'port' => env('DB_PORT_SECOND', '3307'),
    'database' => env('DB_DATABASE_SECOND', 'forge'),
    'username' => env('DB_USERNAME_SECOND', 'forge'),
    'password' => env('DB_PASSWORD_SECOND', ''),
    'unix_socket' => env('DB_SOCKET_SECOND', ''),
    'charset' => env('DB_CHARSET_SECOND', 'utf8mb4'),
    'collation' => env('DB_COLLATION_SECOND', 'utf8mb4_unicode_ci'),
    'prefix' => '',
    'prefix_indexes' => true,
    'strict' => true,
    'engine' => null,
    'options' => extension_loaded('pdo_mysql') ? array_filter([
        PDO::MYSQL_ATTR_SSL_CA => env('MYSQL_ATTR_SSL_CA_SECOND'),
    ]) : [],
],

Docker Compose 容器配置 #

db:
    image: mariadb:11
    container_name: db
    hostname: mariadb
    volumes:
      - paypipol_db:/var/lib/mysql
    restart: always
    ports:
      - '3306:3306'
    environment:
      MYSQL_ROOT_PASSWORD: my_root_password
      MYSQL_DATABASE: x
      MYSQL_USER: root
      MYSQL_PASSWORD: 
    networks:
      - paypipol

db2:
    image: mariadb:11
    container_name: db2
    hostname: mariadb2
    volumes:
      - paypipol_db2:/var/lib/mysql
    restart: always
    ports:
      - '3307:3306'  # Use a different port for the second database
    environment:
      MYSQL_ROOT_PASSWORD: my_root_password
      MYSQL_DATABASE: y
      MYSQL_USER: root
      MYSQL_PASSWORD: 
    networks:
      - paypipol

问题现象 #

执行第二个数据库迁移命令：

docker exec -it backend-dev php artisan migrate --database=mysql_second

出现错误：

Illuminate\Database\QueryException  SQLSTATE[HY000] [2002] Connection timed out (Connection: mysql_second, SQL: select table_name as `name`, (data_length + index_length) as `size`, table_comment as `comment`, engine as `engine`, table_collation as `collation` from information_schema.tables where table_schema = 'y' and table_type in ('BASE TABLE', 'SYSTEM VERSIONED') order by table_name)

已执行排查步骤 #

• db和db2容器均正常运行，可通过MySQL客户端分别连接两个数据库
• 确认.env文件与database.php配置中的凭证和Docker环境变量一致
• 两个容器属于同一Docker网络，理论上可互通

排查方向与解决建议 #

1. Docker网络内主机名与端口使用错误 #

Laravel容器与数据库容器在同一Docker网络内时，不应使用宿主机IP（10.0.0.4）+ 宿主机映射端口（3307），需直接使用数据库容器的hostname或container_name，并使用容器内部端口（3306）：

• 修改.env中第二个数据库配置：

  DB_HOST_SECOND=mariadb2  # 对应db2容器的hostname，或直接用container_name: db2
  DB_PORT_SECOND=3306
  

宿主机端口映射（3307:3306）仅用于外部客户端连接，容器间通信直接用容器内部端口。

2. 数据库权限配置问题 #

检查第二个数据库的root用户是否允许从Laravel容器所在网络访问：

• 进入db2容器执行：

  docker exec -it db2 mysql -uroot -pmy_root_password
  

• 执行权限查询：

  SELECT user, host FROM mysql.user WHERE user='root';
  

如果root用户的host仅为localhost或127.0.0.1，需授权允许从任意主机访问：

GRANT ALL PRIVILEGES ON *.* TO 'root'@'%' IDENTIFIED BY 'my_root_password' WITH GRANT OPTION;
FLUSH PRIVILEGES;

3. Laravel配置缓存问题 #

如果之前执行过php artisan config:cache，修改.env或database.php后需清除缓存：

docker exec -it backend-dev php artisan config:clear

4. 宿主机端口冲突或防火墙限制 #

• 检查宿主机3307端口是否被其他进程占用：

  netstat -tulpn | grep 3307
  

• 临时关闭宿主机防火墙（如ufw、firewalld）测试是否能连接，若恢复正常则需添加端口放行规则。

5. 数据库容器初始化异常 #

查看db2容器日志，确认数据库服务正常启动：

docker logs db2

检查日志中是否有启动失败、权限错误等异常信息。

内容的提问来源于stack exchange，提问作者K. Polash