php connect to mysql failed with:
 PDOException: PDO::__construct(): php_network_getaddresses: getaddrinfo failed: Name or service not known in /var/www/html/test_db_pdo.php:9
Stack trace:
#0 /var/www/html/test_db_pdo.php(9): PDO->__construct('mysql:host=data...', 'root', 'tiger')
#1 {main}

Next PDOException: SQLSTATE[HY000] [2002] php_network_getaddresses: getaddrinfo failed: Name or service not known in /var/www/html/test_db_pdo.php:9
Stack trace:
#0 /var/www/html/test_db_pdo.php(9): PDO->__construct('mysql:host=data...', 'root', 'tiger')
#1 {main}