modified Vagrantfile.erb to override the hostname

Vagrantfile.erb

<% config[:vagrantfiles].each do |vagrantfile| %>
require "<%= vagrantfile %>"
<% end %>

Vagrant.configure("2") do |c|
  c.berkshelf.enabled = false if Vagrant.has_plugin?("vagrant-berkshelf")
  <% if config[:cachier] %>
  if Vagrant.has_plugin?("vagrant-cachier")
    c.cache.scope = <%= [':box', ':machine'].include?(config[:cachier]) ? config[:cachier] : ':box' %>
  end
  <% end %>

  c.vm.box = "<%= config[:box] %>"

<% if config[:box_url] %>
  c.vm.box_url = "<%= config[:box_url] %>"
<% end %>

<% if config[:box_version] %>
  c.vm.box_version = "<%= config[:box_version] %>"
<% end %>

<% if !config[:box_check_update].nil? %>
  c.vm.box_check_update = <%= config[:box_check_update] %>
<% end %>

<% if !config[:box_download_ca_cert].nil? %>
  c.vm.box_download_ca_cert = "<%= config[:box_download_ca_cert] %>"
<% end %>

<% if !config[:box_download_insecure].nil? %>
  c.vm.box_download_insecure = "<%= config[:box_download_insecure] %>"
<% end %>

<% if config[:vm_hostname] %>
  c.vm.hostname = "<%= @instance.name %>.<%= config[:var_domain] ? config[:var_domain] : config[:kitchen_root].split('/')[-1]  %>.<%= config[:var_suffix] ? config[:var_suffix] : "vagrantup.com"  %>"
<% end %>

<% if config[:communicator] %>
  c.vm.communicator = "<%= config[:communicator] %>"
<% end %>

<% if config[:guest] %>
  c.vm.guest = "<%= config[:guest] %>"
<% end %>

<% if config[:communicator] %>
  <% if config[:username] %>
    c.<%= config[:communicator] %>.username = "<%= config[:username] %>"
  <% end %>
  <% if config[:password] %>
    c.<%= config[:communicator] %>.password = "<%= config[:password] %>"
  <% end %>
<% else %>
  <% if config[:username] %>
    c.ssh.username = "<%= config[:username] %>"
  <% end %>
  <% if config[:password] %>
    c.ssh.password = "<%= config[:password] %>"
  <% end %>
<% end %>

<% if config[:ssh_key] %>
  c.ssh.private_key_path = "<%= config[:ssh_key] %>"
<% end %>
<% config[:ssh].each do |key, value| %>
  c.ssh.<%= key %> = <%= [true, false].include?(value) ? value : value.inspect %>
<% end %>
<% if config[:winrm] %>
  <% config[:winrm].each do |key, value| %>
    <% if value.is_a? String %>
      c.winrm.<%= key %> = "<%= value%>"
    <% else  %>
      c.winrm.<%= key %> = <%= value%>
    <% end  %>
  <% end %>
<% end %>

<% if config[:boot_timeout] %>
  c.vm.boot_timeout = <%= config[:boot_timeout] %>
<% end %>

<% Array(config[:network]).each do |opts| %>
  c.vm.network(:<%= opts[0] %>, <%= opts[1..-1].join(", ") %>)
<% end %>

  c.vm.synced_folder ".", "/vagrant", disabled: true
<% config[:synced_folders].each do |source, destination, options| %>
  c.vm.synced_folder <%= source.inspect %>, <%= destination.inspect %>, <%= options %>
<% end %>

  c.vm.provider :<%= config[:provider] %> do |p|
<% case config[:provider]
   when "virtualbox", /^vmware_/
     if config[:gui] == true || config[:gui] == false %>
    p.gui = <%= config[:gui] %>
<%   end
   end

   case config[:provider]
   when "virtualbox", /^vmware_/, "parallels"
     if config[:linked_clone] == true || config[:linked_clone] == false %>
    p.linked_clone = <%= config[:linked_clone] %>
<%   end
   end %>

<% config[:customize].each do |key, value| %>
  <% case config[:provider]
     when "libvirt" %>
    <% if key == :storage %>
      <% if value.is_a? String %>
    p.storage <%= value %>
      <% elsif value.is_a? Array %>
        <% value.each do |v| %>
    p.storage <%= v %>
        <% end %>
      <% end %>
    <% else %>
      <% if value.is_a? String %>
    p.<%= key %> = "<%= value%>"
      <% else %>
    p.<%= key %> = <%= value%>
      <% end %>
    <% end %>
  <% when "lxc" %>
    <% if key == :container_name %>
    p.container_name = <%= value == ":machine" ? value : "\"#{value}\"" %>
    <% elsif key == :backingstore %>
    p.backingstore = "<%= value %>"
    <% elsif key == :backingstore_options %>
      <% config[:customize][:backingstore_options].each do |opt, opt_val| %>
    p.backingstore_option "--<%= opt %>", "<%= opt_val %>"
      <% end %>
    <% elsif key == :include %>
      <% Array(value).each do |include| %>
    p.customize "<%= key %>", "<%= include %>"
      <% end %>
    <% else %>
    p.customize "<%= key %>", "<%= value %>"
    <% end %>
  <% when "managed" %>
    <% if key == :server %>
    p.server = "<%= value %>"
    <% end %>
  <% when "parallels" %>
    <% if key == :memory || key == :cpus %>
    p.<%= key %> = <%= value %>
    <% else %>
    p.customize ["set", :id, "--<%= key.to_s.gsub('_', '-') %>", "<%= value %>"]
    <% end %>
  <% when "softlayer" %>
    <% if key == :disk_capacity %>
    p.<%= key %> = <%= value %>
    <% else %>
    p.<%= key %> = "<%= value %>"
    <% end %>
  <% when "virtualbox" %>
    <% if key == :createhd %>
      <% value = [value] unless value.instance_of?(Array) %>
      <% value.each do |item| %>
    p.customize ["createhd", "--filename", "<%= item[:filename] %>", "--size", <%= item[:size] %>]
      <% end %>
    <% elsif key == :storageattach || key == :storagectl %>
      <% value = [value] unless value.instance_of?(Array) %>
      <% value.each do |item| %>
        <% options = [] %>
        <% item.each do |storage_option_key, storage_option_value|
             options << "\"--#{storage_option_key}\""
             if storage_option_value.instance_of? Fixnum
               options << storage_option_value
             else
               options << "\"#{storage_option_value}\""
             end
           end %>
    p.customize ["<%= key.to_s %>", :id, <%= options.join(', ') %>]
    <% end %>
    <% elsif key == :cpuidset %>
      <% ids = [] %>
      <% value.each do | id |
           ids << "\"#{id}\""
         end %>
    p.customize ["modifyvm", :id, "--cpuidset", <%= ids.join(', ') %>]
    <% else %>
    p.customize ["modifyvm", :id, "--<%= key %>", "<%= value %>"]
    <% end %>
  <% when /^vmware_/ %>
    <% if key == :memory %>
      <% unless config[:customize].include?(:memsize) %>
    p.vmx["memsize"] = "<%= value %>"
      <% end %>
    <% elsif key == :cpus %>
      <% unless config[:customize].include?(:numvcpus) %>
    p.vmx["numvcpus"] = "<%= value %>"
      <% end %>
    <% else %>
    p.vmx["<%= key %>"] = "<%= value %>"
    <% end %>
  <% else %>
    <% if value.is_a? String %>
    p.<%= key %> = "<%= value%>"
    <% else  %>
    p.<%= key %> = <%= value%>
    <% end  %>
  <% end %>
<% end %>
  end

end