Replaced check_call with Popen

backup_vms.py

#!/usr/bin/env python

import contextlib, os, finalize_vm, subprocess

backup_path = '/mnt/backup/tmp/backup'

@contextlib.contextmanager
def flock(path):
    while True:
        try:
            fd = os.open(path, os.O_CREAT | os.O_EXCL | os.O_RDWR)
        else:
            break
    try:
        yield fd
    finally:
        os.close(fd)
        os.unlink(path)

def add_to_backup_store(source):
  dom_name = os.path.basename(source)
  store = '%s/%s' % (store_path, dom_name)
  print subprocess.Popen([
                'duplicity',
                '--name', dom_name, 
                '--no-encryption',
                '--volsize','1024',
                '--tempdir','/dev/shm',
                source, 
                store
               ], stdout=subprocess.PIPE).communicate()[0]

if __name__=="__main__":
  for dom_path in os.listdir(backup_path):
    dom_name = os.path.basename(dom_path)
    lock_file = '%s/%s.lock' % (dom_path, dom_name)
    if not os.path.exists(lock_file):
      with flock(lock_file):
        finalize(os.path.dirname(dom_path), dom_name)
        add_to_backup_store(dom_path)
      rmtree(dom_path)

finalize_vm.py

#!/usr/bin/env python

import libvirt
import sys
import os
import time
from xml.etree import ElementTree

def prepare_xml(xml_file):
  """Function that prepares vm xml for starting on backup machine
     It adds the correct path to disks, changes network to "default" 
     and add '-backup' postfix to machine name"""
  etree = ElementTree.ElementTree()
  tree = etree.parse(xml_file)
  dom_name = tree.find('name').text
  for disk in tree.findall("devices/disk"):
    if disk.get('device') == 'disk':
      dev=disk.find('target').get("dev")
      disk.find('source').set('dev', "%s/%s_%s.%s" % (os.path.dirname(xml_file), dom_name, dev, 'img') )
  for interface in tree.findall('devices/interface'):
    target = interface.find('target')
    interface.remove(target)
    alias = interface.find('alias')
    interface.remove(alias)
    source = interface.find('source')
    source.clear()
    source.set('network', 'default')
  name = dom_name+'-backup'
  tree.find('name').text = name
  return ElementTree.tostring(tree)

def finalize(backup_path, dom_name):
  dom_path = '%s/%s' % (backup_path, dom_name)
  xml_file = '%s/%s.xml' % (dom_path, dom_name)
  dom_xml = prepare_xml(xml_file)
  state = "%s/%s.state" % (dom_path, dom_name)
  timer = 0
  timeout = 120

  conn=libvirt.open("qemu:///system")
  conn.saveImageDefineXML(state, dom_xml, 0)
  network = conn.networkLookupByName('default')
  if not network.isActive():
    network.create()
  try:
    conn.restore(state)
    dom = conn.lookupByName(dom_name+'-backup')
    dom.shutdown()
    print 'Waiting for domain to shutdown'
    while (timer <= timeout):
      try:
        dom_active = dom.isActive()
      except libvirt.libvirtError:
        break
      else:
        if not dom_active:
          break
      time.sleep(1)
      timer += 1
      print '%s...' % timer
    else:
      raise Exception, 'Give up waiting for shutdown, not removing state file'
    print 'Domain has been shutdown, removing state file'
    os.remove(state)
  finally:
    network.destroy()

if __name__=="__main__":
  dom_name = sys.argv[1]
  finalize('/mnt/backup/tmp', dom_name)