nova/nova/virt/hyperv/imagecache.py

139 lines
5.5 KiB
Python

# Copyright 2013 Cloudbase Solutions Srl
# All Rights Reserved.
#
# Licensed under the Apache License, Version 2.0 (the "License"); you may
# not use this file except in compliance with the License. You may obtain
# a copy of the License at
#
# http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
# WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
# License for the specific language governing permissions and limitations
# under the License.
"""
Image caching and management.
"""
import os
from oslo.config import cfg
from oslo.utils import excutils
from oslo.utils import units
from nova.i18n import _
from nova.openstack.common import log as logging
from nova import utils
from nova.virt.hyperv import utilsfactory
from nova.virt.hyperv import vmutils
from nova.virt import images
LOG = logging.getLogger(__name__)
CONF = cfg.CONF
CONF.import_opt('use_cow_images', 'nova.virt.driver')
class ImageCache(object):
def __init__(self):
self._pathutils = utilsfactory.get_pathutils()
self._vhdutils = utilsfactory.get_vhdutils()
def _get_root_vhd_size_gb(self, instance):
try:
# In case of resizes we need the old root disk size
old_flavor = instance.get_flavor('old')
return old_flavor.root_gb
except KeyError:
return instance['root_gb']
def _resize_and_cache_vhd(self, instance, vhd_path):
vhd_info = self._vhdutils.get_vhd_info(vhd_path)
vhd_size = vhd_info['MaxInternalSize']
root_vhd_size_gb = self._get_root_vhd_size_gb(instance)
root_vhd_size = root_vhd_size_gb * units.Gi
root_vhd_internal_size = (
self._vhdutils.get_internal_vhd_size_by_file_size(
vhd_path, root_vhd_size))
if root_vhd_internal_size < vhd_size:
raise vmutils.HyperVException(
_("Cannot resize the image to a size smaller than the VHD "
"max. internal size: %(vhd_size)s. Requested disk size: "
"%(root_vhd_size)s") %
{'vhd_size': vhd_size, 'root_vhd_size': root_vhd_size}
)
if root_vhd_internal_size > vhd_size:
path_parts = os.path.splitext(vhd_path)
resized_vhd_path = '%s_%s%s' % (path_parts[0],
root_vhd_size_gb,
path_parts[1])
@utils.synchronized(resized_vhd_path)
def copy_and_resize_vhd():
if not self._pathutils.exists(resized_vhd_path):
try:
LOG.debug("Copying VHD %(vhd_path)s to "
"%(resized_vhd_path)s",
{'vhd_path': vhd_path,
'resized_vhd_path': resized_vhd_path})
self._pathutils.copyfile(vhd_path, resized_vhd_path)
LOG.debug("Resizing VHD %(resized_vhd_path)s to new "
"size %(root_vhd_size)s",
{'resized_vhd_path': resized_vhd_path,
'root_vhd_size': root_vhd_size})
self._vhdutils.resize_vhd(resized_vhd_path,
root_vhd_internal_size,
is_file_max_size=False)
except Exception:
with excutils.save_and_reraise_exception():
if self._pathutils.exists(resized_vhd_path):
self._pathutils.remove(resized_vhd_path)
copy_and_resize_vhd()
return resized_vhd_path
def get_cached_image(self, context, instance):
image_id = instance.image_ref
base_vhd_dir = self._pathutils.get_base_vhd_dir()
base_vhd_path = os.path.join(base_vhd_dir, image_id)
@utils.synchronized(base_vhd_path)
def fetch_image_if_not_existing():
vhd_path = None
for format_ext in ['vhd', 'vhdx']:
test_path = base_vhd_path + '.' + format_ext
if self._pathutils.exists(test_path):
vhd_path = test_path
break
if not vhd_path:
try:
images.fetch(context, image_id, base_vhd_path,
instance.user_id,
instance.project_id)
format_ext = self._vhdutils.get_vhd_format(base_vhd_path)
vhd_path = base_vhd_path + '.' + format_ext.lower()
self._pathutils.rename(base_vhd_path, vhd_path)
except Exception:
with excutils.save_and_reraise_exception():
if self._pathutils.exists(base_vhd_path):
self._pathutils.remove(base_vhd_path)
return vhd_path
vhd_path = fetch_image_if_not_existing()
if CONF.use_cow_images and vhd_path.split('.')[-1].lower() == 'vhd':
# Resize the base VHD image as it's not possible to resize a
# differencing VHD. This does not apply to VHDX images.
resized_vhd_path = self._resize_and_cache_vhd(instance, vhd_path)
if resized_vhd_path:
return resized_vhd_path
return vhd_path