source: package_branches/invirt-remote/hvirt/host/usr/sbin/invirt-janitor

Last change on this file was 2446, checked in by broder, 15 years ago

Nice the janitorial dds as well as ionicing them.

  • Property svn:executable set to *
File size: 3.7 KB
Line 
1#!/usr/bin/python
2
3"""Clean-up after people's deleted VMs.
4
5The Invirt janitor goes through and finds virtual disk images that
6users have requested we delete. For their privacy, it writes over the
7entire disk with /dev/zero, then removes the logical volume, restoring
8the space to the pool.
9
10A 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
12delete. The janitor notices these requests using inotify.
13"""
14
15
16import os
17import subprocess
18import syslog
19import traceback
20
21import pyinotify
22
23
24_JANITOR_DIR = '/var/lib/invirt-remote/cleanup'
25
26
27def 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            # If the LV name doesn't start with old_, we probably
44            # don't actually want to be deleting it.
45            #
46            # Put it in the try block because we still want to delete
47            # the state file.
48            if not lv.startswith('old_'):
49                continue
50
51            syslog.syslog(syslog.LOG_INFO, "Cleaning up LV '%s'" % lv_path)
52
53            # In a perfect world, this should be erroring out with
54            # ENOSPC, so we ignore errors
55            subprocess.call(['/usr/bin/ionice',
56                             '-c', '2',
57                             '-n', '7',
58                             '/usr/bin/nice',
59                             '/bin/dd',
60                             'if=/dev/zero',
61                             'of=%s' % lv_path,
62                             'bs=1M'])
63
64            # Ignore any errors here, because there's really just not
65            # anything we can do.
66            subprocess.call(['/sbin/lvchange', '-a', 'n', lv_path])
67            subprocess.call(['/sbin/lvchange', '-a', 'ey', lv_path])
68            subprocess.check_call(['/sbin/lvremove', '--force', lv_path])
69
70            syslog.syslog(syslog.LOG_INFO, "Successfully cleaned up LV '%s'" % lv_path)
71        except:
72            syslog.syslog(syslog.LOG_ERR, "Error cleaning up LV '%s':" % lv_path)
73
74            for line in traceback.format_exc().split('\n'):
75                syslog.syslog(syslog.LOG_ERR, line)
76        finally:
77            # Regardless of what happens, we always want to remove the
78            # cleanup queue file, because even if there's an error, we
79            # don't want to waste time wiping the same disk repeatedly
80            os.unlink(os.path.join(_JANITOR_DIR, lv))
81
82
83class Janitor(pyinotify.ProcessEvent):
84    """Process inotify events by wiping and deleting LVs.
85
86    The Janitor class receives inotify events when a new file is
87    created in the state directory.
88    """
89    def process_IN_CREATE(self, event):
90        """Handle a created file or directory.
91
92        When an IN_CREATE event comes in, trigger a cleanup.
93        """
94        cleanup()
95
96
97def main():
98    """Initialize the inotifications and start the main loop."""
99    syslog.openlog('invirt-janitor', syslog.LOG_PID, syslog.LOG_DAEMON)
100
101    watch_manager = pyinotify.WatchManager()
102    janitor = Janitor()
103    notifier = pyinotify.Notifier(watch_manager, janitor)
104    watch_manager.add_watch(_JANITOR_DIR,
105                            pyinotify.EventsCodes.ALL_FLAGS['IN_CREATE'])
106
107    # Before inotifying, run any pending cleanups; otherwise we won't
108    # get notified for them.
109    cleanup()
110
111    while True:
112        notifier.process_events()
113        if notifier.check_events():
114            notifier.read_events()
115
116
117if __name__ == '__main__':
118    main()
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