How to Set Up SSH Keys for Passwordless Login for Ansible

Authentication using SSH keys is a secure and widely-used method for accessing remote systems, particularly in Linux-based environments. Instead of relying on password-based login, SSH key authentication utilizes a cryptographic key pair—a public key and a private key. The public key is stored on the remote server, while the private key remains securely on the user’s local machine. When the user attempts to connect, the server uses the public key to verify the private key, allowing access only if the keys match. This process eliminates the need to transmit passwords over the network, reducing the risk of unauthorized access. Additionally, SSH key authentication can be further secured by adding a passphrase to the private key, offering an extra layer of protection in case the private key is compromised.

Create keypair on the source server, this will create a public and private key

ssh-keygen

This will attempt to create key pair in .ssh directory in current user’s home folder, press enter to keep the defaults. Optionally it will prompt to enter the password for the keys file

The certificate is now generated. The next step is to copy file to destination server. You can use ssh-copy-id utility to transfer file. Once the file is transferred you will see the success message

ssh-copy-id <user>@<remote-computer>

You can now connect to remote server without the need to enter password

In conclusion, authenticating using SSH keys provides a robust, secure alternative to traditional password-based logins for remote access. By leveraging cryptographic key pairs, this method not only strengthens security but also simplifies the login process, especially for frequent connections. The elimination of passwords reduces the risk of brute-force attacks, while adding a passphrase to the private key further enhances protection. Implementing SSH key authentication is a practical and essential step for anyone seeking to safeguard their systems, ensuring both convenience and security in managing remote servers.

Happy Learning 🙂