How to Reset SSH Host Keys when Deploying Linux Templates in Proxmox

In this video, Jay from ‪@LearnLinuxTV‬ will go over how to create a new set of SSH host keys for each instance that you create from an image. Resetting SSH host keys, and making sure that each instance that you set up has different host keys, is vital to server security.
Chapters:
0:00 Introduction
0:50 Creating a VM in Proxmox
3:04 Installing Ubuntu Server
4:37 Resetting the Machine ID
6:12 Demonstrating the Wrong Way to go About This
8:27 Connecting to our VMs
8:56 Locating the Host Keys
9:18 What’s in a Host Key File?
10:08 Demonstrating the Right Way to go About This
11:18 Connecting to Our New VMs
11:41 Resetting the Machine ID
11:55 Creating a Template with Unique Host Keys
13:03 What’s In This Code?
15:39 Change File Permissions
15:52 Move the File
16:20 Restart systemd
16:50 Enable regenerate_ssh_host_keys.service
17:20 Checking the Key Before Regeneration
17:44 Reboot the System
17:55 Creating a Template in Proxmox
18:43 Clone the VM
19:10 Check the New Servers Keys
20:11 Conclusion
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#Linode #Linux #SSHKeys #AlternativeCloud
Product: Linode, SSH Host Keys, Linux; Jay LaCroix;

[@pfos]

Cool! - thanx4 the tips =)

[@MADhatter_AIM]

Perfect, thanks !

[@OsX86H3AvY]

so i might have done this incorrectly but i just ran into the same thing just now, though i installed cockpit onto my template also which opened fine of course but thats where i saw the ssh service had failed...i DID truncate the machine-id, removed ssh host keys, and did an ip address flush just prior to making the template, meaning i have no IP address conflicts, but the ssh service then wont start.....so....i just run sudo apt resintall openssh* and that seems to do fix it..had i known i probably would have NOT installed SSH (i LOVE cockpit....on ubuntu...but i'm an open source freeloader so i dont count) and then i would've installed it afterwards.....maybe next time i make a template ill remember that but for now i just added a note in the clone to remind myself how to fix it

[@BorgSwarm]

This helped me. I couldn't figure out why the SSH service wasnt responding. I also use Cockpit but hadn't checked it yet.

[@mixmastermaverick3336]

You got things a bit mixed up I think. You only get an SSH host key warning if you connect to an IP you previously connected to and it presents a different host key. Connecting to two different IPs that have the same host key won't give a warning. This makes sense, as the same host can have multiple IPs.

[@ALVERMIC]

I wanted to have a ssh key ed25519 but without password and I couldn't make it

[@encapsulatio]

Can you make a guide please on how to install arch packages on debian based distros? and if that is not directly possible then how to correctly convert them to deb packages.

[@RazoBeckett.]

2nd comment

[@LA-MJ]

Writing into urandom is naive. AFAIK it does not really work the way one would think it does. There was a discussion regarding it relatively recently. Early boot randomness is a real problem on entropy-starved systems