http://www.techblogistech.com/2012/03/enabling-sshsftp-updates-in-wordpress-on-amazon-ec2-and-centos/

$ sudo yum install php-devel php-pear libssh2 libssh2-devel
$ sudo pecl install -f ssh2
There’s no need to enter a specific prefix; just press the [enter] key to move forward and it will autodetect the prefix.

echo 'extension=/usr/lib/php/modules/ssh2.so' | sudo tee -a /etc/php.d/ssh2.ini


extension=ssh2.so
/usr/lib/php/modules/ssh2.so
extension=/usr/lib/php/modules/ssh2.so