pdo_mysql extension is not installed

#0 /var/www/app/html/vendor/shardj/zf1-future/library/Zend/Db/Adapter/Abstract.php(460): Varien_Db_Adapter_Pdo_Mysql->_connect()
#1 /var/www/app/html/vendor/shardj/zf1-future/library/Zend/Db/Adapter/Pdo/Abstract.php(267): Zend_Db_Adapter_Abstract->query()
#2 /var/www/app/html/lib/Varien/Db/Adapter/Pdo/Mysql.php(486): Zend_Db_Adapter_Pdo_Abstract->query()
#3 /var/www/app/html/app/code/core/Mage/Core/Model/Resource.php(170): Varien_Db_Adapter_Pdo_Mysql->query()
#4 /var/www/app/html/app/code/core/Mage/Core/Model/Resource.php(101): Mage_Core_Model_Resource->_newConnection()
#5 /var/www/app/html/app/code/core/Mage/Core/Model/Resource/Db/Abstract.php(305): Mage_Core_Model_Resource->getConnection()
#6 /var/www/app/html/app/code/core/Mage/Core/Model/Resource/Db/Abstract.php(338): Mage_Core_Model_Resource_Db_Abstract->_getConnection()
#7 /var/www/app/html/app/code/core/Mage/Core/Model/Resource/Db/Abstract.php(358): Mage_Core_Model_Resource_Db_Abstract->_getReadAdapter()
#8 /var/www/app/html/app/code/core/Mage/Core/Model/Resource/Db/Collection/Abstract.php(121): Mage_Core_Model_Resource_Db_Abstract->getReadConnection()
#9 /var/www/app/html/app/code/core/Mage/Core/Model/Config.php(1478): Mage_Core_Model_Resource_Db_Collection_Abstract->__construct()
#10 /var/www/app/html/app/code/core/Mage/Core/Model/Config.php(1514): Mage_Core_Model_Config->getModelInstance()
#11 /var/www/app/html/app/Mage.php(570): Mage_Core_Model_Config->getResourceModelInstance()
#12 /var/www/app/html/app/code/core/Mage/Core/Model/Abstract.php(259): Mage::getResourceModel()
#13 /var/www/app/html/app/code/core/Mage/Core/Model/Abstract.php(272): Mage_Core_Model_Abstract->getResourceCollection()
#14 /var/www/app/html/app/code/core/Mage/Core/Model/App.php(640): Mage_Core_Model_Abstract->getCollection()
#15 /var/www/app/html/app/code/core/Mage/Core/Model/App.php(495): Mage_Core_Model_App->_initStores()
#16 /var/www/app/html/app/code/core/Mage/Core/Model/App.php(353): Mage_Core_Model_App->_initCurrentStore()
#17 /var/www/app/html/app/Mage.php(761): Mage_Core_Model_App->run()
#18 /var/www/app/html/index.php(59): Mage::run()
#19 {main}