Access remote mysql server(openshift) via codeIgniter

Question

I have added a mysql cartridge in openshift. I wanted to access the mysql server by a simple codeIgniter application running in my localhost. But I can not connect.

here is configuration of mysql

env | grep MYSQL

OPENSHIFT_MYSQL_DB_PORT=3306
OPENSHIFT_MYSQL_DB_HOST=XXX.XXX.XXX.XXX
OPENSHIFT_MYSQL_DB_PASSWORD=password
OPENSHIFT_MYSQL_DB_USERNAME=userame

And here is my /application/config/database.php

$db['default']['hostname'] = 'XXX.XXX.XXX.XXX';
 $db['default']['username'] = 'password';
 $db['default']['password'] = 'username';
 $db['default']['database'] = 'employees';
 $db['default']['dbdriver'] = 'mysql';
 $db['default']['dbprefix'] = '';
 $db['default']['pconnect'] = TRUE;
 $db['default']['db_debug'] = TRUE;
 $db['default']['cache_on'] = FALSE;
 $db['default']['cachedir'] = '';
 $db['default']['char_set'] = 'utf8';
 $db['default']['dbcollat'] = 'utf8_general_ci';
 $db['default']['swap_pre'] = '';
 $db['default']['autoinit'] = TRUE;
 $db['default']['stricton'] = FALSE;

Am I missing something? Can anyone help me with this? Thanks in advance.