From f192a166dcb15ba5939431edfe9bc62ed3372fe2 Mon Sep 17 00:00:00 2001 From: Josh Durgin Date: Mon, 13 Aug 2012 15:13:06 -0700 Subject: rbd: implement create_volume_from_snapshot In an upcoming release, rbd will support creating volumes from snapshots ('cloning'). To clone a snapshot, it must first be 'protected', which means it cannot be deleted until it is unprotected. A snapshot can only be unprotected if no clones depend on it. Thus, translate a failure to unprotect into a SnapshotIsBusy exception. Also check for remaining snapshots before deleting a volume, and raise VolumeIsBusy if any exist. While we're here, tidy up the shell arguments to be more readable. This is backwards compatible since it does not use the new features unless they are available in the installed version of rbd. (cherry picked from cinder commit ff45e32) Change-Id: If4105e7af7ba33f09a15103b53ad675aceb2ebb4 Signed-off-by: Josh Durgin --- nova/volume/driver.py | 68 +++++++++++++++++++++++++++++++++++++++++++++------ 1 file changed, 60 insertions(+), 8 deletions(-) diff --git a/nova/volume/driver.py b/nova/volume/driver.py index d03ad7cdc..a84f0e111 100644 --- a/nova/volume/driver.py +++ b/nova/volume/driver.py @@ -566,30 +566,82 @@ class RBDDriver(VolumeDriver): raise exception.NovaException(_("rbd has no pool %s") % FLAGS.rbd_pool) + def _supports_layering(self): + stdout, _ = self._execute('rbd', '--help') + return 'clone' in stdout + def create_volume(self, volume): """Creates a logical volume.""" if int(volume['size']) == 0: size = 100 else: size = int(volume['size']) * 1024 - self._try_execute('rbd', '--pool', FLAGS.rbd_pool, - '--size', size, 'create', volume['name']) + args = ['rbd', 'create', + '--pool', FLAGS.rbd_pool, + '--size', size, + volume['name']] + if self._supports_layering(): + args += ['--new-format'] + self._try_execute(*args) + + def _clone(self, volume, src_pool, src_image, src_snap): + self._try_execute('rbd', 'clone', + '--pool', src_pool, + '--image', src_image, + '--snap', src_snap, + '--dest-pool', FLAGS.rbd_pool, + '--dest', volume['name']) + + def _resize(self, volume): + size = int(volume['size']) * 1024 + self._try_execute('rbd', 'resize', + '--pool', FLAGS.rbd_pool, + '--image', volume['name'], + '--size', size) + + def create_volume_from_snapshot(self, volume, snapshot): + """Creates a volume from a snapshot.""" + self._clone(volume, FLAGS.rbd_pool, + snapshot['volume_name'], snapshot['name']) + if int(volume['size']): + self._resize(volume) def delete_volume(self, volume): """Deletes a logical volume.""" - self._try_execute('rbd', '--pool', FLAGS.rbd_pool, - 'rm', volume['name']) + stdout, _ = self._execute('rbd', 'snap', 'ls', + '--pool', FLAGS.rbd_pool, + volume['name']) + if stdout.count('\n') > 1: + raise exception.VolumeIsBusy(volume_name=volume['name']) + self._try_execute('rbd', 'rm', + '--pool', FLAGS.rbd_pool, + volume['name']) def create_snapshot(self, snapshot): """Creates an rbd snapshot""" - self._try_execute('rbd', '--pool', FLAGS.rbd_pool, - 'snap', 'create', '--snap', snapshot['name'], + self._try_execute('rbd', 'snap', 'create', + '--pool', FLAGS.rbd_pool, + '--snap', snapshot['name'], snapshot['volume_name']) + if self._supports_layering(): + self._try_execute('rbd', 'snap', 'protect', + '--pool', FLAGS.rbd_pool, + '--snap', snapshot['name'], + snapshot['volume_name']) def delete_snapshot(self, snapshot): """Deletes an rbd snapshot""" - self._try_execute('rbd', '--pool', FLAGS.rbd_pool, - 'snap', 'rm', '--snap', snapshot['name'], + if self._supports_layering(): + try: + self._try_execute('rbd', 'snap', 'unprotect', + '--pool', FLAGS.rbd_pool, + '--snap', snapshot['name'], + snapshot['volume_name']) + except exception.ProcessExecutionError: + raise exception.SnapshotIsBusy(snapshot_name=snapshot['name']) + self._try_execute('rbd', 'snap', 'rm', + '--pool', FLAGS.rbd_pool, + '--snap', snapshot['name'], snapshot['volume_name']) def local_path(self, volume): -- cgit