Connecting to MySQL Server from Applications in OpenPanel

OpenPanel runs each user service inside its own container and uses local networks to isolate them. This means that applications do not connect to the database via localhost or 127.0.0.1, but instead through container hostnames.

For more information about networks: Network Isolation in OpenPanel

To connect from your PHP, Node.js, or Python application to a MySQL/MariaDB database, you must use:

• Hostname: mysql (for MySQL) or mariadb (for MariaDB)
• Port: 3306 (default)
• Username/Password: created for the database from OpenPanel UI

⚠️ Important: Never use localhost or 127.0.0.1 as the database host. These will not work because containers are isolated.

Example: WordPress​

When setting up WordPress inside OpenPanel, use the following database configuration:

DB_HOST=mysql

Here, DB_HOST is set to mysql, so WordPress can reach the MySQL container. If you are using MariaDB, then repalce mysql with mariadb.

Example: Custom PHP Application​

In a custom PHP app, you can connect like this:

<?php
$host = "mysql";       // or "mariadb"
$db   = "my_database";
$user = "my_user";
$pass = "my_password";

$dsn = "mysql:host=$host;dbname=$db;charset=utf8mb4";

try {
    $pdo = new PDO($dsn, $user, $pass);
    echo "Connected successfully!";
} catch (PDOException $e) {
    echo "Connection failed: " . $e->getMessage();
}

Example: Node.js Application​

For Node.js using mysql2 or sequelize:

const mysql = require('mysql2');

const connection = mysql.createConnection({
  host: 'mysql',       // or "mariadb"
  user: 'my_user',
  password: 'my_password',
  database: 'my_database'
});

connection.connect(err => {
  if (err) {
    console.error('Connection error:', err);
    return;
  }
  console.log('Connected successfully!');
});

Example: Python Application​

Using mysql-connector-python:

import mysql.connector

conn = mysql.connector.connect(
    host="mysql",        # or "mariadb"
    user="my_user",
    password="my_password",
    database="my_database"
)

cursor = conn.cursor()
cursor.execute("SELECT DATABASE();")
print("Connected to:", cursor.fetchone())

✅ Summary:

• Use mysql or mariadb as the hostname.
• Never use localhost or 127.0.0.1.
• Works across PHP, WordPress, Node.js, Python, and any other app in the db network.