Configure SSH key login

• Generate a key pair using the command ssh-keygen or use an existing key pair
• Copy the corresponding public key to the root/.ssh/authorized_keys file.

Disable password login

Edit the /etc/ssh/sshd_config file and modify the following parameters:

PubkeyAuthentication yes
PasswordAuthentication no

Restart the SSH service

sudo systemctl restart sshd

If it does not take effect, delete all files in etc/ssh/sshd_config.d .