On a FTP host wordpress updates are very straight forward, just fill your user credentials in the input fields and click the update-button. But what if you are on a amazon ec2 instance with SSH access only. There is no field for your private key or pem-file.
The wordpress plugin “SSH/SFTP Updater Support” adds a text-field and an upload-field for your Amazon EC2 private key to the install-/update-screen. So you can then use the updater for plugin updates and installs and even wordpress system updates.