I am trying to setup webserver with PHP 7 RC3 + Nginx on Ubuntu 14.04 (for test purposes).
I installed Ubuntu in Vagrant using
['class' => 'yii\db\Connection',
'dsn' => 'mysql:host=localhost:3306;dbname=testdb',
'username' => 'user',
'password' => 'password',
'charset' => 'utf8',]
It's simple:
Just provide the port number along with the host name
and set default sock path to your mysql.sock file path in php.ini which the server is running on.