问建立DB连接WordPress (AWS Linux2，MariaDB，Apache)时出错

EN

[mysqld]
datadir=/mnt/disk-1/db-data/mysql/
socket=/mnt/disk-1/db-data/mysql/mysql.sock

[client]
port=3306
socket=/mnt/disk-1/db-data/mysql/mysql.sock

[mariadb]
name = MariaDB
baseurl = http://yum.mariadb.org/10.1/centos7-amd64
gpgkey=https://yum.mariadb.org/RPM-GPG-KEY-MariaDB
gpgcheck=1

MariaDB [(none)]> SELECT @@datadir;
+----------------------------+
| @@datadir                  |
+----------------------------+
| /mnt/disk-1/db-data/mysql/ |
+----------------------------+
1 row in set (0.00 sec)

    DocumentRoot "/mnt/disk-1/www"
    #
    # Relax access to content within /var/www.
    #
    <Directory "/mnt/disk-1/www">
    AllowOverride None
    # Allow open access:
    Require all granted
    </Directory>

    # Further relax access to the default document root:
    <Directory "/mnt/disk-1/www">

    . . .

 // ** MySQL settings - You can get this info from your web host ** //
 /** The name of the database for WordPress */
 define('DB_NAME', 'wpdb');

 /** MySQL database username */
 define('DB_USER', 'user');

 /** MySQL database password */
 define('DB_PASSWORD', 'password');
 /** MySQL hostname */
 define('DB_HOST', 'put-the-private-ip-of-db-instance-here');