Vagrantfile that sets up multiple CentOS 7 VMs and connects them all to a single host-only network

Vagrantfile

# -*- mode: ruby -*-
# vi: set ft=ruby :
#
# Vagrantfile to create a CentOS 7 master and 3 nodes
#
# These VMs can be useful for prototyping new systems such
# as monitoring, mail, configuration management, load balancing
# etc etc.
#
# You will need a Puppet directory structure inside the
# project directory: ./puppet/environments/vagrant/
#
# Requires the following Vagrant plugins:
#   vagrant-puppet-install
#   vagrant-vbguest
#   vagrant-hosts
#
# The above plugins should work just fine on
# Windows 10 as of 2017-08-25
#
# anthonyclarka2 AT G MAIL
#
# Once complete, you should have 1 large "master" VM
# and 3 smaller "node" VMs running CentOS 7 latest.
# They will all have a second, host-only network with
# address 10.0.3.0/24 with addresses as follows:
#
# master = 10.0.3.10
# nodeX = 10.0.3.10X
#
# VMs can thus talk to each other, and you can SSH
# into them directly
#
Vagrant.configure('2') do |config|
  # start with basic latest CentOS 7.x
  # install vbox guest additions
  config.vm.box = 'centos/7'

  # install latest version of puppet
  config.puppet_install.puppet_version = :latest

  # local domain name
  # edit this variable to change the domain name your
  # VMs use!
  ldn = 'test.local'

  # Create the master
  config.vm.define 'master', primary: true do |master|
    # local host name
    lhn                = 'master'
    master.vm.hostname = "#{lhn}.#{ldn}"

    master.vm.network 'private_network', ip: '10.0.3.10'
    master.vm.provision :hosts, sync_hosts: true, add_localhost_hostnames: false

    master.vm.provider 'virtualbox' do |vb|
      vb.name         = 'CentOS 7 Master'
      vb.memory       = 4096
      vb.cpus         = 4
      vb.linked_clone = true
      vb.customize ['modifyvm', :id, '--natdnshostresolver1', 'on']
    end

    master.vm.provision :puppet, run: "always" do |puppet|
      puppet.environment_path = './puppet/environments'
      puppet.environment      = 'vagrant'
    end # end of master config
  end # end of master definition

  # To change the number of nodes built, create an environment variable:
  # export NUM_NODES=4
  num_nodes = ENV['NUM_NODES'] || 3

  # Then create as many nodes as you need:
  # (edit the "3" on the line below to change the number of
  # nodes that get created)
  (1..num_nodes).each do |j|
    # we like zero-padded numbers in our hostnames!
    i = '%02d' % j

    config.vm.define "node#{i}" do |client|
      lhn                = "node#{i}"
      client.vm.hostname = "#{lhn}.#{ldn}"

      # network parameters
      client.vm.network 'private_network', ip: "10.0.3.1#{i}"
      client.vm.provision :hosts, sync_hosts: true, add_localhost_hostnames: false

      client.vm.provider 'virtualbox' do |vb|
        vb.name         = "CentOS 7 Node #{i}"
        vb.memory       = 2048
        vb.cpus         = 2
        vb.linked_clone = true
        vb.customize ['modifyvm', :id, '--natdnshostresolver1', 'on']
      end

      client.vm.provision :puppet, run: "always" do |puppet|
        puppet.environment_path = './puppet/environments'
        puppet.environment      = 'vagrant'
      end # end of puppet config
    end # end of node definition
  end # end of "each do" loop
end