Password-less auto-login with SSH

SSH is widely used with automation scripting, as it makes it possible to remotely execute commands at remote hosts and read their outputs. Usually, SSH is authenticated by using a username and password, which are prompted during the execution of SSH commands. However, providing passwords in automated scripts is impractical, so we need to automate logins. SSH has an in-built feature by which SSH can auto-login using SSH keys. This recipe describes how to create SSH keys and facilitate auto-login.

Getting ready

SSH uses an encryption technique called asymmetric keys consisting of two keys: a public key and a private key for automatic authentication. We can create an authentication key pair using the ssh-keygen command. For automating the authentication, the public key must be placed at the server (by appending the public key to the ~/.ssh/authorized_keys file) and its private key file of the pair should be present at the ~/.ssh directory of the user at the...