Docker部署的WordPress无法连接本地MariaDB数据库求助

我使用Docker官方WordPress镜像部署服务，尝试连接本地主机的MariaDB数据库，但访问http://192.168.18.79:8080时始终显示Error establishing a database connection。

容器启动命令 #

sudo docker run --name  wordpress -p 8080:80 -d 
  -e WORDPRESS_DB_HOST=192.168.18.79 
  -e WORDPRESS_DB_USER='wordpressuser' 
  -e WORDPRESS_DB_PASSWORD='password' 
  -e WORDPRESS_DB_NAME='wordpress_container' 
  -e WORDPRESS_AUTH_KEY='[KEY]' 
  -e WORDPRESS_SECURE_AUTH_KEY='[KEY]' 
  -e WORDPRESS_LOGGED_IN_KEY='[KEY]' 
  -e WORDPRESS_NONCE_KEY='[KEY]' 
  -e WORDPRESS_AUTH_SALT='[KEY]' 
  -e WORDPRESS_SECURE_AUTH_SALT='[KEY]' 
  -e WORDPRESS_LOGGED_IN_SALT='[KEY]' 
  -e WORDPRESS_NONCE_SALT='[KEY]' 
  wordpress

注：[KEY]来自WordPress官方密钥生成工具

已完成的配置操作 #

• 修改MariaDB配置文件/etc/mysql/mariadb.conf.d/50-server.cnf，将bind-address设为0.0.0.0，端口监听状态显示3306已对外开放：

Active Internet connections (only servers)
Proto Recv-Q Send-Q Local Address           Foreign Address         State       PID/Program name    
tcp        0      0 0.0.0.0:8080            0.0.0.0:*               LISTEN      1742/docker-proxy   
tcp        0      0 0.0.0.0:22              0.0.0.0:*               LISTEN      601/sshd: /usr/sbin 
tcp        0      0 0.0.0.0:80              0.0.0.0:*               LISTEN      603/nginx: master p 
tcp        0      0 0.0.0.0:3306            0.0.0.0:*               LISTEN      667/mariadbd
tcp        0      0 0.0.0.0:443             0.0.0.0:*               LISTEN      603/nginx: master p

• 在MariaDB中创建数据库并授权用户：

MariaDB [(none)]> CREATE DATABASE wordpress_container DEFAULT CHARACTER SET utf8 COLLATE utf8_unicode_ci;
MariaDB [(none)]> CREATE USER 'wordpressuser' IDENTIFIED BY 'password';
MariaDB [(none)]> GRANT ALL ON wordpress_container.* TO 'wordpressuser';

• 容器日志显示WordPress初始化正常，但访问时返回500错误：

justin@debian:~$ sudo docker logs wordpress
WordPress not found in /var/www/html - copying now...
Complete! WordPress has been successfully copied to /var/www/html
No 'wp-config.php' found in /var/www/html, but 'WORDPRESS_...' variables supplied; copying 'wp-config-docker.php' (WORDPRESS_AUTH_KEY WORDPRESS_AUTH_SALT WORDPRESS_DB_HOST WORDPRESS_DB_NAME WORDPRESS_DB_PASSWORD WORDPRESS_DB_USER WORDPRESS_LOGGED_IN_KEY WORDPRESS_LOGGED_IN_SALT WORDPRESS_NONCE_KEY WORDPRESS_NONCE_SALT WORDPRESS_SECURE_AUTH_KEY WORDPRESS_SECURE_AUTH_SALT)
AH00558: apache2: Could not reliably determine the server's fully qualified domain name, using 172.17.0.2. Set the 'ServerName' directive globally to suppress this message
AH00558: apache2: Could not reliably determine the server's fully qualified domain name, using 172.17.0.2. Set the 'ServerName' directive globally to suppress this message
[Sun May 26 10:03:28.196354 2024] [mpm_prefork:notice] [pid 1] AH00163: Apache/2.4.59 (Debian) PHP/8.2.19 configured -- resuming normal operations
[Sun May 26 10:03:28.196464 2024] [core:notice] [pid 1] AH00094: Command line: 'apache2 -D FOREGROUND'
172.17.0.1 - - [26/May/2024:10:03:54 +0000] "HEAD / HTTP/1.1" 500 285 "-" "curl/7.88.1"

• 进入容器测试网络连通性：telnet主机3306端口超时，但22端口可正常连接：

justin@debian:~$ sudo docker exec -it wordpress /bin/bash
root@85fef2d89d2f:/var/www/html# telnet 192.168.18.79 3306
Trying 192.168.18.79...
telnet: Unable to connect to remote host: Connection timed out
root@85fef2d89d2f:/var/www/html# telnet 192.168.18.79 22
Trying 192.168.18.79...
Connected to 192.168.18.79.
Escape character is '^]'.
SSH-2.0-OpenSSH_9.2p1 Debian-2+deb12u2

排查与解决方案 #

1. 检查主机防火墙规则 #

Debian常用ufw防火墙，先查看当前规则：

sudo ufw status

如果3306端口未允许Docker子网（默认是172.17.0.0/16）访问，添加规则：

sudo ufw allow from 172.17.0.0/16 to any port 3306

也可以临时关闭防火墙测试是否是拦截问题：

sudo ufw disable

2. 修正MariaDB用户权限 #

之前的授权语句默认仅允许localhost登录，需要修改为允许从Docker子网或任意地址登录：

-- 允许任意地址登录（测试用，生产建议限制子网）
GRANT ALL ON wordpress_container.* TO 'wordpressuser'@'%' IDENTIFIED BY 'password';
-- 仅允许Docker子网登录（更安全）
GRANT ALL ON wordpress_container.* TO 'wordpressuser'@'172.17.0.0/16' IDENTIFIED BY 'password';
-- 刷新权限使配置生效
FLUSH PRIVILEGES;

3. 测试数据库连通性 #

在容器内安装mysql客户端直接测试连接：

sudo docker exec -it wordpress apt update && apt install -y mysql-client
mysql -h 192.168.18.79 -u wordpressuser -p

输入密码后若能成功进入数据库，说明权限和网络正常；若仍失败，再检查防火墙或网络配置。

4. 尝试主机网络模式（测试用） #

如果默认桥接网络有问题，可尝试用主机网络模式启动容器（生产环境不推荐，会暴露容器端口到主机）：

sudo docker run --name wordpress --net=host -d 
  -e WORDPRESS_DB_HOST=127.0.0.1 
  -e WORDPRESS_DB_USER='wordpressuser' 
  -e WORDPRESS_DB_PASSWORD='password' 
  -e WORDPRESS_DB_NAME='wordpress_container' 
  -e WORDPRESS_AUTH_KEY='[KEY]' 
  -e WORDPRESS_SECURE_AUTH_KEY='[KEY]' 
  -e WORDPRESS_LOGGED_IN_KEY='[KEY]' 
  -e WORDPRESS_NONCE_KEY='[KEY]' 
  -e WORDPRESS_AUTH_SALT='[KEY]' 
  -e WORDPRESS_SECURE_AUTH_SALT='[KEY]' 
  -e WORDPRESS_LOGGED_IN_SALT='[KEY]' 
  -e WORDPRESS_NONCE_SALT='[KEY]' 
  wordpress

此时直接访问http://192.168.18.79即可（容器用主机80端口）。

内容的提问来源于stack exchange，提问作者Justin Christian