In this blog, I explore three common methods of setting up passwordless authentication: using SSH keys, SSH-copy-id, and password-less configurations. Passwordless authentication is a secure, efficient way to access remote systems without entering passwords each time, enhancing both convenience and security. I’ll walk through each method, breaking down the setup process for seamless, password-free logins.

I have created 3 EC2 instances on AWS and I will use my local machine as a control node to perform password-less authentication on all the instances

Using SSH Keys

Lets try to perform passwordless authentication on ‘manage-node-1’ using ssh-keys.

I have created private and public keys using this below command

ssh-keygen

it will create .ssh folder and that folder contains private and public key

Connect to manage-node-1 from the AWS console. Copy the control node's public key and paste it into the authorized_keys file on manage-node-1.

Try to log in to manage-node-1 without using a password or any keys.

ssh ubuntu@<public ip address>

Login Successful 🎉

Using SSH-copy-id

Copy the key pair to a safe directory. We will use this key pair to perform passwordless authentication on manage-node-2.

Note: This keypair.pem should be the same one used during the creation of manage-node-2.

ssh-copy-id -f "-o Identityfile <path_of_keypair.pem>" [user@]hostname

Try to log in to manage-node-2 without using a password or any keys.

Login Successful 🎉

Using Password Configuration

Connect to manage-node-3 using AWS Console. Edit this file ‘60-cloudimg-settings.conf” and update ‘PasswordAuthentication yes’

Restart ssh process

sude systemctl restart ssh

Create a password for current user

sudo passwd ubuntu
New Pass:
Retype Pass:

Now, try to connect manage-node-3 from control-node ( laptop ) using ssh-copy-id <username@public ip>

You need to enter the password the first time you connect to manage-node-3. After that, when you try to connect again, it won't ask for a password.

Login Successful 🎉

Conclusion

Setting up passwordless authentication between control and managed nodes enhances both security and efficiency. This method simplifies node management, allowing you to automate tasks securely and focus on more complex DevOps operations.

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