Vagrantfile.yaml:
box_image: 'ubuntu-20.04_mini-20211220'
interface: 'eno1'
systems:
 smar02: ''

---
Vagrantfile:

# -*- mode: ruby -*-
# vi: set ft=ruby :

require 'yaml'

current_dir    = File.dirname(File.expand_path(__FILE__))
myconfigs        = YAML.load_file("#{current_dir}/Vagrantfile.yaml")

myhostnames = myconfigs['systems']
myinterface = myconfigs['interface']
mybox_image = myconfigs['box_image']

Vagrant.configure("2") do |config|
 myhostnames.each do |i,x|
  config.vm.boot_timeout = 900
  config.vm.define vm_name = "#{i}" do |subconfig|
   subconfig.vm.box = mybox_image
   subconfig.ssh.username = "vmadmin"
   subconfig.ssh.password = "vmadmin"
   subconfig.vm.hostname = "#{i}"
   subconfig.vm.network :public_network, auto_config: false, bridge: myinterface
   subconfig.vm.provision "shell", inline: <<-SHELL
    /bin/touch /tmp/firstrun
   SHELL
   subconfig.vm.provider "virtualbox" do |v|
    v.name = vm_name
    v.customize ["modifyvm", :id, "--paravirtprovider", "kvm"]
    v.customize ["modifyvm", :id, "--autostart-enabled", "on"]
    v.customize ["modifyvm", :id, "--nictype1", "virtio"]
    v.customize ["modifyvm", :id, "--nictype2", "virtio"]
   end
  end
 end
end