yii2 控制台任务 linux环境问题 [ 2.0 版本 ]

php simtest/yii mytimer
出错提示

Exception 'yii\db\Exception' with message 'could not find driver'

in /var/www/vhosts/simtest/vendor/yiisoft/yii2/db/Connection.php:547

Stack trace:
#0 /var/www/vhosts/simtest/vendor/yiisoft/yii2/db/Connection.php(858): yii\db\Co                                                                                        nnection->open()
#1 /var/www/vhosts/simtest/vendor/yiisoft/yii2/db/Connection.php(845): yii\db\Co                                                                                        nnection->getMasterPdo()
#2 /var/www/vhosts/simtest/vendor/yiisoft/yii2/db/Command.php(219): yii\db\Conne                                                                                        ction->getSlavePdo()

这个该怎么处理