Two Machine Virtual Network With Debian 11 Bullseye and Vagrant

Start a two computer virtual network in minutes.

Vagrant

Automatically sets up Virtualbox machines
Automates SSH login
No graphical user interface is needed

Install Vagrant

With Debian and Ubuntu, it's easy

$ sudo apt-get update
$ sudo apt-get install vagrant virtualbox

With Mac and Windows, you should download the installers and next-next a couple of times.

Vagrantfile

Create a new directory for your project, and save this Vagrantfile into it.

$ mkdir twohost/; cd twohost/
$ nano Vagrantfile

# -*- mode: ruby -*-
# vi: set ft=ruby :
# Copyright 2019-2021 Tero Karvinen http://TeroKarvinen.com

$tscript = <<TSCRIPT
set -o verbose
apt-get update
apt-get -y install tree
echo "Done - set up test environment - https://terokarvinen.com/search/?q=vagrant"
TSCRIPT

Vagrant.configure("2") do |config|
	config.vm.synced_folder ".", "/vagrant", disabled: true
	config.vm.synced_folder "shared/", "/home/vagrant/shared", create: true
	config.vm.provision "shell", inline: $tscript
	config.vm.box = "debian/bullseye64"

	config.vm.define "t001" do |t001|
		t001.vm.hostname = "t001"
		t001.vm.network "private_network", ip: "192.168.88.101"
	end

	config.vm.define "t002", primary: true do |t002|
		t002.vm.hostname = "t002"
		t002.vm.network "private_network", ip: "192.168.88.102"
	end
	
end

Enjoy your two hosts

You can ssh login to a host with

$ vagrant ssh t001

And exit back to your host OS

vagrant@t001$ exit

Both hosts can connect to each other and the Internet.

$ vagrant ssh t001
vagrant@t001$ ping -c 1 192.168.88.102
vagrant@t001$ ping -c 1 8.8.8.8 # Google nameserver
vagrant@t001$ exit

$ vagrant ssh t002
vagrant@t002$ ping -c 1 192.168.88.101
vagrant@t002$ exit

Destroy

Best part, it's so quick and easy you can just destroy your virtual machines and start fresh.

$ vagrant destroy # all files on both virtual machines are destroyed

And then get fresh, empty machines

$ vagrant up

Nice way to practice: got something working? Now destroy the machines, do it again from scratch. Rinse and repeat.

Got it working? How do you like it? Feel free to comment below.

Troubleshooting

If it works, you're done. If not, read on.

Error: "IP numbers not allowed" (or something like that) when running 'vagrant up'.

Some systems limit what addresses can be chosen. The allowed range is in the error message, you can feed it to ipcalc if you want to see lowest and highest allowed address. For example, 'ipcalc 192.168.56.0/21'. Simply change the IP address in Vagrantfile to allowed range. Here, I just changed the second to last number 88 to 60.

t001.vm.network "private_network", ip: "192.168.60.101"
# ...
t002.vm.network "private_network", ip: "192.168.60.102"

Adminstrivia

Vagrantfile is extracted from my earlier longer Vagrantfiles. Updated: added troubleshooting in case the allowed IP range differs.