host/usr/sbin/invirt-janitor

   1 #!/usr/bin/python
   2
   3 """Clean-up after people's deleted VMs.
   4
   5 The Invirt janitor goes through and finds virtual disk images that
   6 users have requested we delete. For their privacy, it writes over the
   7 entire disk with /dev/zero, then removes the logical volume, restoring
   8 the space to the pool.
   9
  10 A request is indicated to the janitor by creating a file in
  11 /var/lib/invirt-remote/cleanup/ corresponding to the name of the LV to
  12 delete. The janitor notices these requests using inotify.
  13 """
  14
  15
  16 import os
  17 import subprocess
  18 import syslog
  19 import traceback
  20
  21 import pyinotify
  22
  23
  24 _JANITOR_DIR = '/var/lib/invirt-remote/cleanup'
  25
  26
  27 def cleanup():
  28     """Actually cleanup deleted LVs.
  29
  30     When triggered, continue to iterate over cleanup queue files,
  31     deleting LVs one at a time, until there are no more pending
  32     cleanups.
  33     """
  34     while True:
  35         lvs = os.listdir(_JANITOR_DIR)
  36         if not lvs:
  37             break
  38
  39         lv = lvs.pop()
  40         lv_path = '/dev/xenvg/%s' % lv
  41
  42         try:
  43             syslog.syslog(syslog.LOG_INFO, "Cleaning up LV '%s'" % lv_path)
  44
  45             subprocess.check_call(['/usr/bin/ionice',
  46                                    '-c', '2',
  47                                    '-n', '7',
  48                                    '/bin/dd',
  49                                    'if=/dev/zero',
  50                                    'of=%s' % lv_path,
  51                                    'bs=1M'])
  52
  53             # Ignore any errors here, because there's really just not
  54             # anything we can do.
  55             subprocess.call(['/sbin/lvchange', '-a', 'n', lv_path])
  56             subprocess.call(['/sbin/lvchange', '-a', 'ey', lv_path])
  57             subprocess.check_call(['/sbin/lvremove', '--force', lv_path])
  58
  59             syslog.syslog(syslog.LOG_INFO, "Successfully cleaned up LV '%s'" % lv_path)
  60         except:
  61             syslog.syslog(syslog.LOG_ERR, "Error cleaning up LV '%s':" % lv_path)
  62
  63             for line in traceback.format_exc().split('\n'):
  64                 syslog.syslog(syslog.LOG_ERR, line)
  65         finally:
  66             # Regardless of what happens, we always want to remove the
  67             # cleanup queue file, because even if there's an error, we
  68             # don't want to waste time wiping the same disk repeatedly
  69             os.unlink(os.path.join(_JANITOR_DIR, lv))
  70
  71
  72 class Janitor(pyinotify.ProcessEvent):
  73     """Process inotify events by wiping and deleting LVs.
  74
  75     The Janitor class receives inotify events when a new file is
  76     created in the state directory.
  77     """
  78     def process_IN_CREATE(self, event):
  79         """Handle a created file or directory.
  80
  81         When an IN_CREATE event comes in, trigger a cleanup.
  82         """
  83         cleanup()
  84
  85
  86 def main():
  87     """Initialize the inotifications and start the main loop."""
  88     syslog.openlog('invirt-janitor', syslog.LOG_PID, syslog.LOG_DAEMON)
  89
  90     watch_manager = pyinotify.WatchManager()
  91     janitor = Janitor()
  92     notifier = pyinotify.Notifier(watch_manager, janitor)
  93     watch_manager.add_watch(_JANITOR_DIR,
  94                             pyinotify.EventsCodes.ALL_FLAGS['IN_CREATE'])
  95
  96     # Before inotifying, run any pending cleanups; otherwise we won't
  97     # get notified for them.
  98     cleanup()
  99
 100     while True:
 101         notifier.process_events()
 102         if notifier.check_events():
 103             notifier.read_events()
 104
 105
 106 if __name__ == '__main__':
 107     main()