由于驱动程序缺失，无法安装yii2 mongodb扩展

我试图安装yii2 mongodb扩展，但我有这个错误，当我运行作曲家更新

Problem 1
    - yiisoft/yii2-mongodb 2.1.1 requires ext-mongodb >=1.0.0 -> the requested PHP extension mongodb is missing from your system.
    - yiisoft/yii2-mongodb 2.1.0 requires ext-mongodb >=1.0.0 -> the requested PHP extension mongodb is missing from your system.
    - Installation request for yiisoft/yii2-mongodb ~2.1.0 -> satisfiable by yiisoft/yii2-mongodb[2.1.0, 2.1.1].

我知道我需要安装驱动程序，但我有它，我知道因为这个

php -i | grep mongo
/etc/php5/cli/conf.d/20-mongo.ini,
mongo
mongo.allow_empty_keys => 0 => 0
mongo.chunk_size => 261120 => 261120
mongo.cmd => $ => $
mongo.default_host => localhost => localhost
mongo.default_port => 27017 => 27017
mongo.is_master_interval => 15 => 15
mongo.long_as_object => 0 => 0
mongo.native_long => 1 => 1
mongo.ping_interval => 5 => 5

和扩展是通过pecl安装的，当我运行

pecl info mongo
About pecl.php.net/mongo-1.6.14
===============================
Release Type          PECL-style PHP extension (source code)
Name                  mongo
Channel               pecl.php.net
Summary               MongoDB database driver
Description           This package provides an interface for
                      communicating with the MongoDB database in PHP.
Maintainers           Derick Rethans <derick@php.net> (lead)
                      Hannes Magnusson <bjori@php.net> (lead)
                      Jeremy Mikola <jmikola@php.net> (lead)
Release Date          2016-04-26 16:08:28
Release Version       1.6.14 (stable)
API Version           1.6.14 (stable)

错误的原因是什么?任何帮助将不胜感激，谢谢!!