Create an SSH Key Pair

Instances take an SSH public key at boot. Generate the pair on the machine you connect from.

Create the key pair

ssh-keygen -t ed25519

Accept the default path and set a passphrase when prompted.

$ ssh-keygen -t ed25519
Generating public/private ed25519 key pair.
Enter file in which to save the key (/home/user/.ssh/id_ed25519):
Enter passphrase for "/home/user/.ssh/id_ed25519" (empty for no passphrase):
Enter same passphrase again:
Your identification has been saved in /home/user/.ssh/id_ed25519
Your public key has been saved in /home/user/.ssh/id_ed25519.pub

This writes two files:

File	Purpose
~/.ssh/id_ed25519	Private key. Never share it.
~/.ssh/id_ed25519.pub	Public key. Upload this to the cloud.

Use -t rsa -b 4096 instead if you need a key for a system that does not support Ed25519.

View the public key

$ cat ~/.ssh/id_ed25519.pub
ssh-ed25519 AAAAC3NzaC1lZDI1NTE5AAAAIK8Qb5tVxQ3mHhE2vN7pYrWfJ4sLdTgXcZ9aUmKoPqRs user@workstation

Next

Import the public key into the cloud, then select it when launching an instance. See Add a key pair in How to Create an Instance.

Connect to the instance with the matching private key:

ssh -i ~/.ssh/id_ed25519 <user>@<floating-ip>