250 lines
9.9 KiB
Python
250 lines
9.9 KiB
Python
# Copyright 2013 Cloudbase Solutions Srl
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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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"""
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Image caching and management.
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"""
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import os
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import re
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from os_win import utilsfactory
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from oslo_log import log as logging
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from oslo_utils import excutils
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from oslo_utils import units
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from oslo_utils import uuidutils
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import nova.conf
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from nova import exception
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from nova.i18n import _
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from nova import utils
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from nova.virt.hyperv import pathutils
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from nova.virt import imagecache
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from nova.virt import images
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LOG = logging.getLogger(__name__)
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CONF = nova.conf.CONF
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class ImageCache(imagecache.ImageCacheManager):
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def __init__(self):
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super(ImageCache, self).__init__()
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self._pathutils = pathutils.PathUtils()
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self._vhdutils = utilsfactory.get_vhdutils()
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def _get_root_vhd_size_gb(self, instance):
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if instance.old_flavor:
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return instance.old_flavor.root_gb
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else:
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return instance.flavor.root_gb
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def _resize_and_cache_vhd(self, instance, vhd_path):
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vhd_size = self._vhdutils.get_vhd_size(vhd_path)['VirtualSize']
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root_vhd_size_gb = self._get_root_vhd_size_gb(instance)
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root_vhd_size = root_vhd_size_gb * units.Gi
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root_vhd_internal_size = (
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self._vhdutils.get_internal_vhd_size_by_file_size(
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vhd_path, root_vhd_size))
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if root_vhd_internal_size < vhd_size:
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raise exception.FlavorDiskSmallerThanImage(
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flavor_size=root_vhd_size, image_size=vhd_size)
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if root_vhd_internal_size > vhd_size:
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path_parts = os.path.splitext(vhd_path)
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resized_vhd_path = '%s_%s%s' % (path_parts[0],
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root_vhd_size_gb,
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path_parts[1])
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lock_path = os.path.dirname(resized_vhd_path)
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lock_name = "%s-cache.lock" % os.path.basename(resized_vhd_path)
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@utils.synchronized(name=lock_name, external=True,
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lock_path=lock_path)
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def copy_and_resize_vhd():
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if not self._pathutils.exists(resized_vhd_path):
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try:
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LOG.debug("Copying VHD %(vhd_path)s to "
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"%(resized_vhd_path)s",
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{'vhd_path': vhd_path,
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'resized_vhd_path': resized_vhd_path})
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self._pathutils.copyfile(vhd_path, resized_vhd_path)
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LOG.debug("Resizing VHD %(resized_vhd_path)s to new "
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"size %(root_vhd_size)s",
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{'resized_vhd_path': resized_vhd_path,
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'root_vhd_size': root_vhd_size})
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self._vhdutils.resize_vhd(resized_vhd_path,
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root_vhd_internal_size,
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is_file_max_size=False)
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except Exception:
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with excutils.save_and_reraise_exception():
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if self._pathutils.exists(resized_vhd_path):
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self._pathutils.remove(resized_vhd_path)
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copy_and_resize_vhd()
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return resized_vhd_path
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def get_cached_image(self, context, instance, rescue_image_id=None):
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image_id = rescue_image_id or instance.image_ref
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base_vhd_dir = self._pathutils.get_base_vhd_dir()
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base_vhd_path = os.path.join(base_vhd_dir, image_id)
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lock_name = "%s-cache.lock" % image_id
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@utils.synchronized(name=lock_name, external=True,
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lock_path=base_vhd_dir)
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def fetch_image_if_not_existing():
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vhd_path = None
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for format_ext in ['vhd', 'vhdx']:
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test_path = base_vhd_path + '.' + format_ext
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if self._pathutils.exists(test_path):
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vhd_path = test_path
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break
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if not vhd_path:
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try:
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images.fetch(context, image_id, base_vhd_path)
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format_ext = self._vhdutils.get_vhd_format(base_vhd_path)
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vhd_path = base_vhd_path + '.' + format_ext.lower()
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self._pathutils.rename(base_vhd_path, vhd_path)
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except Exception:
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with excutils.save_and_reraise_exception():
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if self._pathutils.exists(base_vhd_path):
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self._pathutils.remove(base_vhd_path)
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return vhd_path
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vhd_path = fetch_image_if_not_existing()
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# Note: rescue images are not resized.
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is_vhd = vhd_path.split('.')[-1].lower() == 'vhd'
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if CONF.use_cow_images and is_vhd and not rescue_image_id:
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# Resize the base VHD image as it's not possible to resize a
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# differencing VHD. This does not apply to VHDX images.
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resized_vhd_path = self._resize_and_cache_vhd(instance, vhd_path)
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if resized_vhd_path:
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return resized_vhd_path
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if rescue_image_id:
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self._verify_rescue_image(instance, rescue_image_id,
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vhd_path)
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return vhd_path
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def _verify_rescue_image(self, instance, rescue_image_id,
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rescue_image_path):
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rescue_image_info = self._vhdutils.get_vhd_info(rescue_image_path)
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rescue_image_size = rescue_image_info['VirtualSize']
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flavor_disk_size = instance.flavor.root_gb * units.Gi
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if rescue_image_size > flavor_disk_size:
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err_msg = _('Using a rescue image bigger than the instance '
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'flavor disk size is not allowed. '
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'Rescue image size: %(rescue_image_size)s. '
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'Flavor disk size:%(flavor_disk_size)s.') % dict(
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rescue_image_size=rescue_image_size,
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flavor_disk_size=flavor_disk_size)
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raise exception.ImageUnacceptable(reason=err_msg,
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image_id=rescue_image_id)
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def get_image_details(self, context, instance):
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image_id = instance.image_ref
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return images.get_info(context, image_id)
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def _age_and_verify_cached_images(self, context, all_instances, base_dir):
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for img in self.originals:
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if img in self.used_images:
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# change the timestamp on the image so as to reflect the last
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# time it was used
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self._update_image_timestamp(img)
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elif CONF.image_cache.remove_unused_base_images:
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self._remove_if_old_image(img)
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def _update_image_timestamp(self, image):
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backing_files = self._get_image_backing_files(image)
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for img in backing_files:
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os.utime(img, None)
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def _get_image_backing_files(self, image):
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base_file = self._pathutils.get_image_path(image)
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if not base_file:
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# not vhd or vhdx, ignore.
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return []
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backing_files = [base_file]
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resize_re = re.compile('%s_[0-9]+$' % image)
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for img in self.unexplained_images:
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match = resize_re.match(img)
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if match:
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backing_files.append(self._pathutils.get_image_path(img))
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return backing_files
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def _remove_if_old_image(self, image):
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backing_files = self._get_image_backing_files(image)
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max_age_seconds = (
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CONF.image_cache.remove_unused_original_minimum_age_seconds)
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for img in backing_files:
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age_seconds = self._pathutils.get_age_of_file(img)
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if age_seconds > max_age_seconds:
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LOG.info("Removing old, unused image: %s", img)
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self._remove_old_image(img)
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def _remove_old_image(self, image_path):
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lock_path = os.path.dirname(image_path)
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lock_name = "%s-cache.lock" % os.path.basename(image_path)
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@utils.synchronized(name=lock_name, external=True,
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lock_path=lock_path)
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def _image_synchronized_remove():
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self._pathutils.remove(image_path)
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_image_synchronized_remove()
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def update(self, context, all_instances):
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base_vhd_dir = self._pathutils.get_base_vhd_dir()
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running = self._list_running_instances(context, all_instances)
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self.used_images = running['used_images'].keys()
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all_files = self._list_base_images(base_vhd_dir)
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self.originals = all_files['originals']
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self.unexplained_images = all_files['unexplained_images']
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self._age_and_verify_cached_images(context, all_instances,
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base_vhd_dir)
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def _list_base_images(self, base_dir):
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unexplained_images = []
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originals = []
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for entry in os.listdir(base_dir):
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file_name, extension = os.path.splitext(entry)
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# extension has a leading '.'. E.g.: '.vhdx'
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if extension.lstrip('.').lower() not in ['vhd', 'vhdx']:
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# File is not an image. Ignore it.
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# imagecache will not store images of any other formats.
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continue
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if uuidutils.is_uuid_like(file_name):
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originals.append(file_name)
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else:
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unexplained_images.append(file_name)
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return {'unexplained_images': unexplained_images,
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'originals': originals}
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