serverspec files testing multiple hosts at once. How to get a summary report of host failures?

gistfile1.rb

$ cat Rakefile
require 'rake'
require 'rspec/core/rake_task'

hosts = %w(
   atlspf01
   atlspf02
   atlspf03
   atlspf04
)

task :spec    => 'spec:all'

namespace :spec do
  hosts.each do |host|
    begin
      RSpec::Core::RakeTask.new(host) do |t|
        ENV['TARGET_HOST'] = host
        t.pattern = "spec/base,cfengine3/*_spec.rb"
    rescue
    end
  end
end

$ cat spec/spec_helper.rb 
require 'serverspec'
require 'net/ssh'

set :backend, :ssh

if ENV['ASK_SUDO_PASSWORD']
  begin
    require 'highline/import'
  rescue LoadError
    fail "highline is not available. Try installing it."
  end
  set :sudo_password, ask("Enter sudo password: ") { |q| q.echo = false }
else
  set :sudo_password, ENV['SUDO_PASSWORD']
end

host = ENV['TARGET_HOST']

options = Net::SSH::Config.for(host)

options[:user] ||= Etc.getlogin

host_run_on = options[:host_name] || host
 
set :host,        host_run_on
set :ssh_options, options
 
RSpec.configure do |c|
   c.after(:each) do |example|
      if example.exception
        puts "Failed on #{host_run_on}"
      end
   end
end


$ cat spec/cfengine3/common_spec.rb 
require 'spec_helper'
require 'socket'

describe "All common tests" do
   describe package('cfengine-community') do
      it { should be_installed }
   end

   describe command( '/var/cfengine/bin/cf-promises --version') do
      its(:stdout) { should match /3\.6\.5/ }
   end

   describe service( 'cfengine3' ) do
      it { should be_enabled }
   end

   for proc in [ 'execd', 'serverd', 'monitord' ]
      describe process( "cf-#{proc}" ) do
         it { should be_running }
      end
   end

   describe port(5308) do
     it { should be_listening }
   end
end

$ rspec
Password:  
..Failed on []
F....

Failures:

  1) All common tests Service "cfengine3" should be enabled
     Failure/Error: it { should be_enabled }
       expected Service "cfengine3" to be enabled
       sudo -p 'Password: ' /bin/sh -c chkconfig\ --list\ cfengine3\ \|\ grep\ 3:on
       
     # ./spec/cfengine3/common_spec.rb:14:in `block (3 levels) in <top (required)>'

Finished in 12.96 seconds (files took 1.4 seconds to load)
7 examples, 1 failure

Failed examples:

rspec ./spec/cfengine3/common_spec.rb:14 # All common tests Service "cfengine3" should be enabled