In invirt-remote:

[invirt/packages/invirt-remote.git] / host / usr / sbin / invirt-janitor

diff --git a/host/usr/sbin/invirt-janitor b/host/usr/sbin/invirt-janitor
new file mode 100755 (executable)
index 0000000..75a637a
--- /dev/null
+++ b/host/usr/sbin/invirt-janitor
@@ -0,0 +1,107 @@
+#!/usr/bin/python
+
+"""Clean-up after people's deleted VMs.
+
+The Invirt janitor goes through and finds virtual disk images that
+users have requested we delete. For their privacy, it writes over the
+entire disk with /dev/zero, then removes the logical volume, restoring
+the space to the pool.
+
+A request is indicated to the janitor by creating a file in
+/var/lib/invirt-remote/cleanup/ corresponding to the name of the LV to
+delete. The janitor notices these requests using inotify.
+"""
+
+
+import os
+import subprocess
+import syslog
+import traceback
+
+import pyinotify
+
+
+_JANITOR_DIR = '/var/lib/invirt-remote/cleanup'
+
+
+def cleanup():
+    """Actually cleanup deleted LVs.
+
+    When triggered, continue to iterate over cleanup queue files,
+    deleting LVs one at a time, until there are no more pending
+    cleanups.
+    """
+    while True:
+        lvs = os.listdir(_JANITOR_DIR)
+        if not lvs:
+            break
+
+        lv = lvs.pop()
+        lv_path = '/dev/xenvg/%s' % lv
+
+        try:
+            syslog.syslog(syslog.LOG_INFO, "Cleaning up LV '%s'" % lv_path)
+
+            subprocess.check_call(['/usr/bin/ionice',
+                                   '-c', '2',
+                                   '-n', '7',
+                                   '/bin/dd',
+                                   'if=/dev/zero',
+                                   'of=%s' % lv_path,
+                                   'bs=1M'])
+
+            # Ignore any errors here, because there's really just not
+            # anything we can do.
+            subprocess.call(['/sbin/lvchange', '-a', 'n', lv_path])
+            subprocess.call(['/sbin/lvchange', '-a', 'ey', lv_path])
+            subprocess.check_call(['/sbin/lvremove', '--force', lv_path])
+
+            syslog.syslog(syslog.LOG_INFO, "Successfully cleaned up LV '%s'" % lv_path)
+        except:
+            syslog.syslog(syslog.LOG_ERR, "Error cleaning up LV '%s':" % lv_path)
+
+            for line in traceback.format_exc().split('\n'):
+                syslog.syslog(syslog.LOG_ERR, line)
+        finally:
+            # Regardless of what happens, we always want to remove the
+            # cleanup queue file, because even if there's an error, we
+            # don't want to waste time wiping the same disk repeatedly
+            os.unlink(os.path.join(_JANITOR_DIR, lv))
+
+
+class Janitor(pyinotify.ProcessEvent):
+    """Process inotify events by wiping and deleting LVs.
+
+    The Janitor class receives inotify events when a new file is
+    created in the state directory.
+    """
+    def process_IN_CREATE(self, event):
+        """Handle a created file or directory.
+
+        When an IN_CREATE event comes in, trigger a cleanup.
+        """
+        cleanup()
+
+
+def main():
+    """Initialize the inotifications and start the main loop."""
+    syslog.openlog('invirt-janitor', syslog.LOG_PID, syslog.LOG_DAEMON)
+
+    watch_manager = pyinotify.WatchManager()
+    janitor = Janitor()
+    notifier = pyinotify.Notifier(watch_manager, janitor)
+    watch_manager.add_watch(_JANITOR_DIR,
+                            pyinotify.EventsCodes.ALL_FLAGS['IN_CREATE'])
+
+    # Before inotifying, run any pending cleanups; otherwise we won't
+    # get notified for them.
+    cleanup()
+
+    while True:
+        notifier.process_events()
+        if notifier.check_events():
+            notifier.read_events()
+
+
+if __name__ == '__main__':
+    main()