Create KVM guest using fog/libvirt and a QCOW2 template

fog_kvm_create_from_template.rb

require 'fog'
require 'net/ssh'
require 'net/scp'


def upload_file(host, user, password, source, dest, print_progress = true)
  Net::SSH.start(host, user, :password => password) do |ssh|
    puts "Uploading file... (#{File.basename(source)})"
    ssh.scp.upload!(source, dest) do |ch, name, sent, total|
      if print_progress
        print "\rProgress: #{(sent.to_f * 100 / total.to_f).to_i}% completed"
      end
    end
  end
  puts if print_progress
end

client = Fog::Compute.new({ 
                     :provider => "libvirt" ,
                     :libvirt_uri => "qemu+ssh://root@blackops/system"
                   })

require 'pp'
#
# List VM names
# not required, just demoing
client.servers.each do |s|
  puts s.name
end

# 
# List pools info
# not required, just demoing
#
client.pools.all.each do |p|
  puts p.name
  puts p.uuid
  puts p.capacity
  puts p.allocation
  puts p.capacity - p.allocation # Free Space
end

#
# Create a test volume
# not required, just demoing
#
client.volumes.create :name => 'test-vol-foo.qcow2',
                      :allocation => "#{File.size('centos5-jeos-ip-info.qcow2')/1024/1024}M",
                      :capacity => '4G',
                      :format_type => 'qcow2',
                      :pool_name => 'default'

#
# create the domain/guest with a 10G volume (sparse/thin)
# 
s = client.servers.create :name => 'fog-test',
                          :volume_allocation => "#{File.size('centos5-jeos-ip-info.qcow2')/1024/1024}M",
                          :volume_capacity => '10G',
                          :volume_format_type => 'qcow2',
                          #:autostart => true, # Starting guest automatically
                          :volume_pool_name => 'default'

#
# Upload our template to replace de volume created with servers.create
#
upload_file('blackops', 'root', '', 'centos5-jeos-ip-info.qcow2', '/var/lib/libvirt/images/fog-test.qcow2') 

#
# Start the guest
#
s.start