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# vim: tabstop=4 shiftwidth=4 softtabstop=4
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# Copyright 2012 Grid Dynamics
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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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# http://www.apache.org/licenses/LICENSE-2.0
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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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from nova import flags
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from nova.openstack.common import cfg
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from nova.openstack.common import excutils
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from nova import utils
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from nova.virt.disk import api as disk
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from nova.virt.libvirt import config
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from nova.virt.libvirt import utils as libvirt_utils
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__imagebackend_opts = [
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cfg.StrOpt('libvirt_images_type',
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help='VM Images format. Acceptable values are: raw, qcow2, lvm,'
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' default. If default is specified,'
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' then use_cow_images flag is used instead of this one.'),
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cfg.StrOpt('libvirt_images_volume_group',
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help='LVM Volume Group that is used for VM images, when you'
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' specify libvirt_images_type=lvm.'),
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cfg.BoolOpt('libvirt_sparse_logical_volumes',
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help='Create sparse logical volumes (with virtualsize)'
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' if this flag is set to True.'),
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FLAGS.register_opts(__imagebackend_opts)
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__metaclass__ = abc.ABCMeta
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def __init__(self, instance, name, suffix):
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"""Image initialization.
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:instance: Instance name.
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:suffix: Suffix for image name.
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def create_image(self, prepare_template, base, size, *args, **kwargs):
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"""Create image from template.
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Contains specific behavior for each image type.
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:prepare_template: function, that creates template.
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Should accept `target` argument.
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:size: Size of created image in bytes
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def libvirt_info(self, device_type):
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"""Get `LibvirtConfigGuestDisk` filled for this image.
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:device_type: Device type for this image.
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def cache(self, fn, fname, size=None, *args, **kwargs):
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"""Creates image from template.
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Ensures that template and image not already exists.
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Ensures that base directory exists.
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Synchronizes on template fetching.
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:fn: function, that creates template.
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Should accept `target` argument.
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:size: Size of created image in bytes (optional)
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@utils.synchronized(fname)
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def call_if_not_exists(target, *args, **kwargs):
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if not os.path.exists(target):
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fn(target=target, *args, **kwargs)
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if not os.path.exists(self.path):
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base_dir = os.path.join(FLAGS.instances_path, '_base')
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if not os.path.exists(base_dir):
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libvirt_utils.ensure_tree(base_dir)
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base = os.path.join(base_dir, fname)
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self.create_image(call_if_not_exists, base, size,
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def __init__(self, instance, name, suffix):
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self.path = os.path.join(FLAGS.instances_path,
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instance, name + suffix)
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def libvirt_info(self, device_type):
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info = config.LibvirtConfigGuestDisk()
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info.source_type = 'file'
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info.source_device = device_type
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info.driver_format = 'raw'
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info.source_path = self.path
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def create_image(self, prepare_template, base, size, *args, **kwargs):
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@utils.synchronized(base)
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def copy_raw_image(base, target, size):
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libvirt_utils.copy_image(base, target)
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disk.extend(target, size)
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generating = 'image_id' not in kwargs
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#Generating image in place
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prepare_template(target=self.path, *args, **kwargs)
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prepare_template(target=base, *args, **kwargs)
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with utils.remove_path_on_error(self.path):
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copy_raw_image(base, self.path, size)
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def libvirt_info(self, device_type):
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info = config.LibvirtConfigGuestDisk()
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info.source_type = 'file'
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info.source_device = device_type
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info.driver_format = 'qcow2'
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info.source_path = self.path
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def create_image(self, prepare_template, base, size, *args, **kwargs):
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@utils.synchronized(base)
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def copy_qcow2_image(base, target, size):
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size_gb = size / (1024 * 1024 * 1024)
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qcow2_base += '_%d' % size_gb
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if not os.path.exists(qcow2_base):
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with utils.remove_path_on_error(qcow2_base):
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libvirt_utils.copy_image(base, qcow2_base)
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disk.extend(qcow2_base, size)
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libvirt_utils.create_cow_image(qcow2_base, target)
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prepare_template(target=base, *args, **kwargs)
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with utils.remove_path_on_error(self.path):
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copy_qcow2_image(base, self.path, size)
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return fname.replace('_', '__')
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def libvirt_info(self, device_type):
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info = config.LibvirtConfigGuestDisk()
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info.source_type = 'block'
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info.source_device = device_type
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info.driver_format = 'raw'
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info.source_path = self.path
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def __init__(self, instance, name, suffix):
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if not FLAGS.libvirt_images_volume_group:
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raise RuntimeError(_('You should specify'
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' libvirt_images_volume_group'
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' flag to use LVM images.'))
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self.vg = FLAGS.libvirt_images_volume_group
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self.lv = '%s_%s' % (self.escape(instance),
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self.escape(name + suffix))
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self.path = os.path.join('/dev', self.vg, self.lv)
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self.sparse = FLAGS.libvirt_sparse_logical_volumes
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def create_image(self, prepare_template, base, size, *args, **kwargs):
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@utils.synchronized(base)
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def create_lvm_image(base, size):
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base_size = disk.get_image_virtual_size(base)
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resize = size > base_size
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size = size if resize else base_size
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libvirt_utils.create_lvm_image(self.vg, self.lv,
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size, sparse=self.sparse)
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cmd = ('dd', 'if=%s' % base, 'of=%s' % self.path, 'bs=4M')
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utils.execute(*cmd, run_as_root=True)
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disk.resize2fs(self.path)
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generated = 'ephemeral_size' in kwargs
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#Generate images with specified size right on volume
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if generated and size:
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libvirt_utils.create_lvm_image(self.vg, self.lv,
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size, sparse=self.sparse)
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with self.remove_volume_on_error(self.path):
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prepare_template(target=self.path, *args, **kwargs)
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prepare_template(target=base, *args, **kwargs)
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with self.remove_volume_on_error(self.path):
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create_lvm_image(base, size)
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@contextlib.contextmanager
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def remove_volume_on_error(self, path):
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with excutils.save_and_reraise_exception():
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libvirt_utils.remove_logical_volumes(path)
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class Backend(object):
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def __init__(self, use_cow):
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'default': Qcow2 if use_cow else Raw
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def image(self, instance, name,
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suffix=None, image_type=None):
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"""Constructs image for selected backend
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:instance: Instance name.
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:suffix: Suffix for image name (optional).
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:image_type: Image type.
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Optional, is FLAGS.libvirt_images_type by default.
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image_type = FLAGS.libvirt_images_type
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image = self.BACKEND.get(image_type)
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raise RuntimeError(_('Unknown image_type=%s') % image_type)
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return image(instance, name, suffix)
added
removed
nova/virt/libvirt/imagebackend.py
