My vagrant file...better example of how easy it is to add new servers

Vagrantfile

domain = 'familyguy.com'

VAGRANTFILE_API_VERSION = "2"
VAGRANT_BOX_URL = "http://developer.nrel.gov/downloads/vagrant-boxes/CentOS-6.4-x86_64-v20130731.box"
VAGRANT_TMP_NAME = "centos-min"
VBGUI = false

nodes = [
  { :hostname => 'peter', :ip => '192.168.2.10', :box => 'centos-min' },
  { :hostname => 'lois', :ip => '192.168.2.11', :box => 'centos-min' },
  { :hostname => 'stewie', :ip => '192.168.2.12', :box => 'centos-min'},
  { :hostname => 'brian', :ip => '192.168.2.13', :box => 'centos-min'},
]

Vagrant.configure(VAGRANTFILE_API_VERSION) do |config|
  
  #If template box is not installed download and install and name centos-min

  config.vm.box_url = VAGRANT_BOX_URL
  config.vm.box     = VAGRANT_TMP_NAME

  nodes.each do |node|
      config.vm.define node[:hostname] do |node_config|
        node_config.vm.box = node[:box]
        node_config.vm.host_name = node[:hostname] + '.' + domain
        node_config.vm.network :private_network, ip: node[:ip]
      
        
        #Set memory default to 480MB if not defined in nodes array
        memory = node[:ram] ? node[:ram] : 480;
        node_config.vm.provider :virtualbox do |vb|
        
          #Set VBGUI to true if you want to troubleshoot the bootup of the VM's
          vb.gui = VBGUI
          #Modify the vm's config..most important (--name) this changes the name in the virtualbox interface
          vb.customize ['modifyvm', :id, '--name', node[:hostname], '--memory', memory.to_s ]
       end
     end
  end

  #Sets up the puppet provisioner so it can be used to provisioin the server.
  #config.vm.provision :puppet do |puppet|
  #  puppet.manifests_path = 'puppet/manifests'
  #  puppet.manifest_file = 'site.pp'
  #  puppet.module_path   = 'puppet/modules'
  #end
end