In this article I will describe how to access linux servers using ssh keys instead of using normal password authentication.
Login to local ssh terminal and generate ssh key with strong passphrase
# ssk-keygen -t rsa 2048
then copy the generated /root/.ssh/id_rsa.pub to the remote server (which you want to access using ssh keys) and then append its content to the file /root/.ssh/authorized_keys using the command
# cat id_rsa.pub >> /root/.ssh/authorized_keys