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OpenStack Study: imagecache.py**** CubicPower OpenStack Study ****
# 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 nova.compute import flavors from nova.openstack.common import excutils from nova.openstack.common.gettextutils import _ from nova.openstack.common import log as logging from nova.openstack.common import units 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')
**** CubicPower OpenStack Study **** class ImageCache(object):
**** CubicPower OpenStack Study **** def __init__(self): self._pathutils = utilsfactory.get_pathutils() self._vhdutils = utilsfactory.get_vhdutils()
**** CubicPower OpenStack Study **** def _get_root_vhd_size_gb(self, instance): try: # In case of resizes we need the old root disk size old_flavor = flavors.extract_flavor( instance, prefix='old_') return old_flavor['root_gb'] except KeyError: return instance['root_gb']
**** CubicPower OpenStack Study **** 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
**** CubicPower OpenStack Study **** 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
**** CubicPower OpenStack Study **** 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
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