Remote Linux servers can be administered using SSH. Normally, local machine can connect to these servers using SSH using user id/password combination. Local machine can also be configured to remote into these servers using SSH without password.
To make it work we have to generate a public/private key pair using ssh-keygen, and subsequently copy the public key using ssh-copy-id to remote server’s authorized_keys file.
The simplest use is:
$ ssh-keygen
$ ssh-copy-id -i ~/.ssh/id_rsa.pub remote_server
For more information, there is a very informative blog written about this here.