doctrine:
    dbal:
        default_connection: default
        connections:
            default:
                driver:   pdo_mysql
                host:     '%database_host%'
                port:     '%database_port%'
                dbname:   '%database_name%'
                user:     '%database_user%'
                password: '%database_password%'
                charset:  UTF8
            customer:
                driver:   pdo_mysql
                host:     '%database_host2%'
                port:     '%database_port2%'
                dbname:   '%database_name2%'
                user:     '%database_user2%'
                password: '%database_password2%'
                charset:  UTF8
    orm:
        default_entity_manager: default
        entity_managers:
            default:
                connection: default
                mappings:
                    AppBundle:  ~
                    AcmeStoreBundle: ~
            customer:
                connection: customer
                mappings:
                    AcmeCustomerBundle: ~

class UserController extends Controller
{
    public function indexAction()
    {
        // All three return the "default" entity manager
        $em = $this->get('doctrine')->getManager();
        $em = $this->get('doctrine')->getManager('default');
        $em = $this->get('doctrine.orm.default_entity_manager');
        // Both of these return the "customer" entity manager
        $customerEm = $this->get('doctrine')->getManager('customer');
        $customerEm = $this->get('doctrine.orm.customer_entity_manager');
    }
}

/** @var EntityManager $em */
$em = $this->getDoctrine()->getManager();
$conn = $em->getConnection();
$users = $conn->fetchAll('SELECT * FROM users');