Authentication without password using OpenSSH Key, certificates .pem and .pub

[miguelgfierro]

Based on this tutorial.

How to generate a Key Pair for authentication without password

ssh-keygen -t rsa -b 2048 -v

We have to add the keyname migonzagpup100_rsa:

Generating public/private rsa key pair.
Enter file in which to save the key (/Users/miguel/.ssh/id_rsa): /Users/miguel/.ssh/migonzagpup100_rsa
Enter passphrase (empty for no passphrase): 
Enter same passphrase again: 
Your identification has been saved in /Users/miguel/.ssh/migonzagpup100_rsa.
Your public key has been saved in /Users/miguel/.ssh/migonzagpup100_rsa.pub.
The key fingerprint is:
SHA256:2VVHKEfxyzrawPDUzrYvK/WbMLlvYK/6PzUBCKoWmW4 miguel@user1s-MacBook-Pro.local
The key's randomart image is:

You get two files, migonzagpup100_rsa.pub and migonzagpup100_rsa.

Uploading the generated certificate from client computer to server

Then we need to copy the public key to the server

ssh-copy-id -i /Users/miguel/.ssh/migonzagpup100_rsa.pub hoaphumanoid@migonzagpup100.westeurope.cloudapp.azure.com

Now we make sure that we can log in using the private key (without the password):

ssh -i /Users/miguel/.ssh/migonzagpup100_rsa hoaphumanoid@migonzagpup100.westeurope.cloudapp.azure.com

Authenticating directly through hostname

You can create the file ~/.ssh/config and add the following lines:

Host migonzagpup100 migonzagpup100.westeurope.cloudapp.azure.com
Hostname migonzagpup100.westeurope.cloudapp.azure.com
User hoaphumanoid
IdentityFile /Users/miguel/.ssh/migonzagpup100_rsa

Host migonzagpup100london migonzagpup100london.westeurope.cloudapp.azure.com
Hostname migonzagpup100london.westeurope.cloudapp.azure.com
User hoaphumanoid
IdentityFile /Users/miguel/.ssh/migonzagpup100london

Now you can ssh to the machine directly by using the hostname: ssh migonzagpup100.