add ability to clone images
Given the backend location from Glance, drivers can determine whether they can clone or otherwise efficiently create a volume from the image without downloading all the data from Glance. For now implement cloning for the RBD driver. There's already a Glance backend that stores images as RBD snapshots, so they're ready to be cloned into volumes. Fall back to copying all the data if cloning is not possible. Change-Id: I71a8172bd22a5bbf64d4c68631630125fcc7fd34 Implements: blueprint efficient-volumes-from-images Signed-off-by: Josh Durgin <josh.durgin@inktank.com>
This commit is contained in:
Josh Durgin
parent
87ba5de73e
commit
edc11101cb
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@ -0,0 +1,161 @@
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# vim: tabstop=4 shiftwidth=4 softtabstop=4
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# Copyright 2012 Josh Durgin
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# All Rights Reserved.
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#
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# Licensed under the Apache License, Version 2.0 (the "License"); you may
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# not use this file except in compliance with the License. You may obtain
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# a copy of the License at
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#
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# http://www.apache.org/licenses/LICENSE-2.0
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#
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# Unless required by applicable law or agreed to in writing, software
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# distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
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# WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
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# License for the specific language governing permissions and limitations
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# under the License.
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from cinder import db
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from cinder import exception
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from cinder.openstack.common import log as logging
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from cinder.openstack.common import timeutils
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from cinder import test
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from cinder.tests.image import fake as fake_image
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from cinder.tests.test_volume import DriverTestCase
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from cinder.volume.driver import RBDDriver
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LOG = logging.getLogger(__name__)
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class RBDTestCase(test.TestCase):
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def setUp(self):
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super(RBDTestCase, self).setUp()
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def fake_execute(*args):
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pass
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self.driver = RBDDriver(execute=fake_execute)
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def test_good_locations(self):
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locations = [
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'rbd://fsid/pool/image/snap',
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'rbd://%2F/%2F/%2F/%2F',
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]
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map(self.driver._parse_location, locations)
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def test_bad_locations(self):
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locations = [
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'rbd://image',
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'http://path/to/somewhere/else',
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'rbd://image/extra',
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'rbd://image/',
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'rbd://fsid/pool/image/',
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'rbd://fsid/pool/image/snap/',
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'rbd://///',
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]
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for loc in locations:
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self.assertRaises(exception.ImageUnacceptable,
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self.driver._parse_location,
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loc)
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self.assertFalse(self.driver._is_cloneable(loc))
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def test_cloneable(self):
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self.stubs.Set(self.driver, '_get_fsid', lambda: 'abc')
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location = 'rbd://abc/pool/image/snap'
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self.assertTrue(self.driver._is_cloneable(location))
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def test_uncloneable_different_fsid(self):
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self.stubs.Set(self.driver, '_get_fsid', lambda: 'abc')
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location = 'rbd://def/pool/image/snap'
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self.assertFalse(self.driver._is_cloneable(location))
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def test_uncloneable_unreadable(self):
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def fake_exc(*args):
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raise exception.ProcessExecutionError()
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self.stubs.Set(self.driver, '_get_fsid', lambda: 'abc')
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self.stubs.Set(self.driver, '_execute', fake_exc)
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location = 'rbd://abc/pool/image/snap'
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self.assertFalse(self.driver._is_cloneable(location))
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class FakeRBDDriver(RBDDriver):
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def _clone(self):
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pass
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def _resize(self):
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pass
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class ManagedRBDTestCase(DriverTestCase):
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driver_name = "cinder.tests.test_rbd.FakeRBDDriver"
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def setUp(self):
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super(ManagedRBDTestCase, self).setUp()
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fake_image.stub_out_image_service(self.stubs)
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def _clone_volume_from_image(self, expected_status,
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clone_works=True):
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"""Try to clone a volume from an image, and check the status
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afterwards"""
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def fake_clone_image(volume, image_location):
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pass
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def fake_clone_error(volume, image_location):
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raise exception.CinderException()
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self.stubs.Set(self.volume.driver, '_is_cloneable', lambda x: True)
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if clone_works:
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self.stubs.Set(self.volume.driver, 'clone_image', fake_clone_image)
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else:
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self.stubs.Set(self.volume.driver, 'clone_image', fake_clone_error)
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image_id = 'c905cedb-7281-47e4-8a62-f26bc5fc4c77'
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volume_id = 1
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# creating volume testdata
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db.volume_create(self.context, {'id': volume_id,
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'updated_at': timeutils.utcnow(),
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'display_description': 'Test Desc',
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'size': 20,
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'status': 'creating',
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'instance_uuid': None,
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'host': 'dummy'})
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try:
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if clone_works:
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self.volume.create_volume(self.context,
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volume_id,
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image_id=image_id)
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else:
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self.assertRaises(exception.CinderException,
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self.volume.create_volume,
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self.context,
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volume_id,
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image_id=image_id)
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volume = db.volume_get(self.context, volume_id)
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self.assertEqual(volume['status'], expected_status)
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finally:
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# cleanup
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db.volume_destroy(self.context, volume_id)
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def test_clone_image_status_available(self):
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"""Verify that before cloning, an image is in the available state."""
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self._clone_volume_from_image('available', True)
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def test_clone_image_status_error(self):
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"""Verify that before cloning, an image is in the available state."""
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self._clone_volume_from_image('error', False)
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def test_clone_success(self):
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self.stubs.Set(self.volume.driver, '_is_cloneable', lambda x: True)
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self.stubs.Set(self.volume.driver, 'clone_image', lambda a, b: True)
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image_id = 'c905cedb-7281-47e4-8a62-f26bc5fc4c77'
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self.assertTrue(self.volume.driver.clone_image({}, image_id))
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def test_clone_bad_image_id(self):
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self.stubs.Set(self.volume.driver, '_is_cloneable', lambda x: True)
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self.assertFalse(self.volume.driver.clone_image({}, None))
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def test_clone_uncloneable(self):
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self.stubs.Set(self.volume.driver, '_is_cloneable', lambda x: False)
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self.assertFalse(self.volume.driver.clone_image({}, 'dne'))
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@ -116,7 +116,7 @@ class API(base.Base):
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if image_id:
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# check image existence
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image_meta = self.image_service.show(context, image_id)
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image_size_in_gb = image_meta['size'] / GB
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image_size_in_gb = int(image_meta['size']) / GB
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#check image size is not larger than volume size.
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if image_size_in_gb > size:
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msg = _('Size of specified image is larger than volume size.')
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@ -20,7 +20,9 @@ Drivers for volumes.
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"""
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import tempfile
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import time
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import urllib
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from cinder import exception
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from cinder import flags
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@ -64,6 +66,10 @@ volume_opts = [
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default=None,
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help='the libvirt uuid of the secret for the rbd_user'
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'volumes'),
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cfg.StrOpt('volume_tmp_dir',
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default=None,
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help='where to store temporary image files if the volume '
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'driver does not write them directly to the volume'),
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]
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FLAGS = flags.FLAGS
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@ -245,6 +251,17 @@ class VolumeDriver(object):
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"""Copy the volume to the specified image."""
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raise NotImplementedError()
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def clone_image(self, volume, image_location):
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"""Create a volume efficiently from an existing image.
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image_location is a string whose format depends on the
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image service backend in use. The driver should use it
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to determine whether cloning is possible.
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Returns a boolean indicating whether cloning occurred
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"""
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return False
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class ISCSIDriver(VolumeDriver):
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"""Executes commands relating to ISCSI volumes.
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@ -642,6 +659,72 @@ class RBDDriver(VolumeDriver):
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def terminate_connection(self, volume, connector):
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pass
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def _parse_location(self, location):
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prefix = 'rbd://'
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if not location.startswith(prefix):
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reason = _('Image %s is not stored in rbd') % location
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raise exception.ImageUnacceptable(reason)
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pieces = map(urllib.unquote, location[len(prefix):].split('/'))
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if any(map(lambda p: p == '', pieces)):
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reason = _('Image %s has blank components') % location
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raise exception.ImageUnacceptable(reason)
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if len(pieces) != 4:
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reason = _('Image %s is not an rbd snapshot') % location
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raise exception.ImageUnacceptable(reason)
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return pieces
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def _get_fsid(self):
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stdout, _ = self._execute('ceph', 'fsid')
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return stdout.rstrip('\n')
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def _is_cloneable(self, image_location):
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try:
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fsid, pool, image, snapshot = self._parse_location(image_location)
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except exception.ImageUnacceptable:
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return False
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if self._get_fsid() != fsid:
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reason = _('%s is in a different ceph cluster') % image_location
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LOG.debug(reason)
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return False
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# check that we can read the image
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try:
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self._execute('rbd', 'info',
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'--pool', pool,
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'--image', image,
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'--snap', snapshot)
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except exception.ProcessExecutionError:
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LOG.debug(_('Unable to read image %s') % image_location)
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return False
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return True
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def clone_image(self, volume, image_location):
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if image_location is None or not self._is_cloneable(image_location):
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return False
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_, pool, image, snapshot = self._parse_location(image_location)
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self._clone(volume, pool, image, snapshot)
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self._resize(volume)
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return True
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def copy_image_to_volume(self, context, volume, image_service, image_id):
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# TODO(jdurgin): replace with librbd
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# this is a temporary hack, since rewriting this driver
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# to use librbd would take too long
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if FLAGS.volume_tmp_dir and not os.exists(FLAGS.volume_tmp_dir):
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os.makedirs(FLAGS.volume_tmp_dir)
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with tempfile.NamedTemporaryFile(dir=FLAGS.volume_tmp_dir) as tmp:
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image_service.download(context, image_id, tmp)
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# import creates the image, so we must remove it first
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self._try_execute('rbd', 'rm',
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'--pool', FLAGS.rbd_pool,
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volume['name'])
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self._try_execute('rbd', 'import',
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'--pool', FLAGS.rbd_pool,
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tmp.name, volume['name'])
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class SheepdogDriver(VolumeDriver):
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"""Executes commands relating to Sheepdog Volumes"""
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@ -112,23 +112,32 @@ class VolumeManager(manager.SchedulerDependentManager):
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# before passing it to the driver.
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volume_ref['host'] = self.host
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if image_id:
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status = 'downloading'
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else:
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status = 'available'
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status = 'available'
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model_update = False
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try:
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vol_name = volume_ref['name']
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vol_size = volume_ref['size']
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LOG.debug(_("volume %(vol_name)s: creating lv of"
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" size %(vol_size)sG") % locals())
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if snapshot_id is None:
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if snapshot_id is None and image_id is None:
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model_update = self.driver.create_volume(volume_ref)
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else:
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elif snapshot_id is not None:
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snapshot_ref = self.db.snapshot_get(context, snapshot_id)
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model_update = self.driver.create_volume_from_snapshot(
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volume_ref,
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snapshot_ref)
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else:
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# create the volume from an image
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image_service, image_id = \
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glance.get_remote_image_service(context,
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image_id)
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image_location = image_service.get_location(context, image_id)
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cloned = self.driver.clone_image(volume_ref, image_location)
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if not cloned:
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model_update = self.driver.create_volume(volume_ref)
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status = 'downloading'
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if model_update:
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self.db.volume_update(context, volume_ref['id'], model_update)
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@ -148,7 +157,7 @@ class VolumeManager(manager.SchedulerDependentManager):
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LOG.debug(_("volume %s: created successfully"), volume_ref['name'])
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self._reset_stats()
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if image_id:
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if image_id and not cloned:
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#copy the image onto the volume.
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self._copy_image_to_volume(context, volume_ref, image_id)
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return volume_ref['id']
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