wordpress后台自动更新需要提供ftp密码，但是如果云主机只开通了ssh，则无法进行自动更新，需要下载一个SSH SFTP Updater Support 插件

Keeping your WordPress install up-to-date and installing plugins in a hassle-free manner is not so easy if your server uses SFTP. “SSH SFTP Updater Support” for WordPress uses phpseclib to remedy this deficiency.

插件下载地址:http://wordpress.org/plugins/ssh-sftp-updater-support/ 目前0.4版