This gist will add a cd that has an iso to vsphere 5.1

add_cd_to_vmware.rb

#!/usr/bin/env ruby
require 'yaml'
require 'rbvmomi'

hosts = ['VCenter host']
datacenters = ['datacenter']
templates = ['relativepath/vm']
mount = true

config_file = File.expand_path('~/.fog')

found_file = File.file?(config_file)
if "#{config_file}" == 'false'
  puts 'The ~/.fog file does not exist'
else
  puts "loading file"
  mycreds = YAML.load_file(config_file)

  #create loop 
  #log_in = #RbVmomi::VIM.connect host:
  log_in = RbVmomi::VIM.connect host:"#{hosts[0]}", user: "#{mycreds['vsphere_username']}", password: "#{mycreds['vsphere_password']}", insecure: true
  
  #create loop
  dc = log_in.serviceInstance.find_datacenter("#{datacenters[0]}") or fail "datacenter not found"
  vm = dc.find_vm("#{templates[0]}") or fail "VM not found"
  d_obj = vm.config.hardware.device.select {|hw| hw.class == RbVmomi::VIM::VirtualCdrom}.first
  machine_conf_spec = RbVmomi::VIM::VirtualMachineConfigSpec(
                                                             deviceChange: [{
                                                               operation: :edit,
                                                               device: RbVmomi::VIM::VirtualCdrom(
                                                                 backing: d_obj.backing,
                                                                 key: d_obj.key,
                                                                 controllerKey: d_obj.controllerKey,
                                                                 connectable: RbVmomi::VIM::VirtualDeviceConnectInfo(
                                                                   startConnected: "#{mount}",
                                                                   connected: "#{mount}",
                                                                   allowGuestControl: true)
)}])

vm.ReconfigVM_Task(spec: machine_conf_spec).wait_for_completion
  
end