yii2数据库读写分离db配置

<?php
return [
    'class'     => 'yii\db\Connection',
    'charset'     => 'utf8',

    //多主多从
    'masters'        => [
            ['dsn' => 'mysql:host=localhost;dbname=master1','charset' => 'utf8',],
            ['dsn' => 'mysql:host=localhost;dbname=master2','charset' => 'utf8',],
    ],
    'masterConfig'    =>  [
           'username'     => 'root',
           'password'     => '',
           'attributes' => [
               // use a smaller connection timeout
               PDO::ATTR_TIMEOUT => 10,
          ],
    ],

    'slaves'        => [
            ['dsn' => 'mysql:host=localhost;dbname=slave1','charset' => 'utf8',],
            ['dsn' => 'mysql:host=localhost;dbname=slave2','charset' => 'utf8',],
            ['dsn' => 'mysql:host=localhost;dbname=slave3','charset' => 'utf8',],
    ],
    'slaveConfig'    =>  [
           'username'     => 'root',
           'password'     => '',
           'attributes' => [
               // use a smaller connection timeout
               PDO::ATTR_TIMEOUT => 10,
          ],
    ],

];
?>