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OpenStack Study: vhdutilsv2.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. """ Utility class for VHD related operations. Based on the "root/virtualization/v2" namespace available starting with Hyper-V Server / Windows Server 2012. """ import struct import sys if sys.platform == 'win32': import wmi from nova.openstack.common.gettextutils import _ from nova.openstack.common import units from nova.virt.hyperv import constants from nova.virt.hyperv import vhdutils from nova.virt.hyperv import vmutils from nova.virt.hyperv import vmutilsv2 from xml.etree import ElementTree VHDX_BAT_ENTRY_SIZE = 8 VHDX_HEADER_OFFSETS = [64 * units.Ki, 128 * units.Ki] VHDX_HEADER_SECTION_SIZE = units.Mi VHDX_LOG_LENGTH_OFFSET = 68 VHDX_METADATA_SIZE_OFFSET = 64 VHDX_REGION_TABLE_OFFSET = 192 * units.Ki VHDX_BS_METADATA_ENTRY_OFFSET = 48
**** CubicPower OpenStack Study **** class VHDUtilsV2(vhdutils.VHDUtils): _VHD_TYPE_DYNAMIC = 3 _VHD_TYPE_DIFFERENCING = 4 _vhd_format_map = { constants.DISK_FORMAT_VHD: 2, constants.DISK_FORMAT_VHDX: 3, }
**** CubicPower OpenStack Study **** def __init__(self): self._vmutils = vmutilsv2.VMUtilsV2() if sys.platform == 'win32': self._conn = wmi.WMI(moniker='//./root/virtualization/v2')
**** CubicPower OpenStack Study **** def create_dynamic_vhd(self, path, max_internal_size, format): vhd_format = self._vhd_format_map.get(format) if not vhd_format: raise vmutils.HyperVException(_("Unsupported disk format: %s") % format) self._create_vhd(self._VHD_TYPE_DYNAMIC, vhd_format, path, max_internal_size=max_internal_size)
**** CubicPower OpenStack Study **** def create_differencing_vhd(self, path, parent_path): parent_vhd_info = self.get_vhd_info(parent_path) self._create_vhd(self._VHD_TYPE_DIFFERENCING, parent_vhd_info["Format"], path, parent_path=parent_path)
**** CubicPower OpenStack Study **** def _create_vhd(self, vhd_type, format, path, max_internal_size=None, parent_path=None): vhd_info = self._conn.Msvm_VirtualHardDiskSettingData.new() vhd_info.Type = vhd_type vhd_info.Format = format vhd_info.Path = path vhd_info.ParentPath = parent_path if max_internal_size: vhd_info.MaxInternalSize = max_internal_size image_man_svc = self._conn.Msvm_ImageManagementService()[0] (job_path, ret_val) = image_man_svc.CreateVirtualHardDisk( VirtualDiskSettingData=vhd_info.GetText_(1)) self._vmutils.check_ret_val(ret_val, job_path)
**** CubicPower OpenStack Study **** def reconnect_parent_vhd(self, child_vhd_path, parent_vhd_path): image_man_svc = self._conn.Msvm_ImageManagementService()[0] vhd_info_xml = self._get_vhd_info_xml(image_man_svc, child_vhd_path) # Can't use ".//PROPERTY[@NAME='ParentPath']/VALUE" due to # compatibility requirements with Python 2.6 et = ElementTree.fromstring(vhd_info_xml) for item in et.findall("PROPERTY"): name = item.attrib["NAME"] if name == 'ParentPath': item.find("VALUE").text = parent_vhd_path break vhd_info_xml = ElementTree.tostring(et) (job_path, ret_val) = image_man_svc.SetVirtualHardDiskSettingData( VirtualDiskSettingData=vhd_info_xml) self._vmutils.check_ret_val(ret_val, job_path)
**** CubicPower OpenStack Study **** def _get_resize_method(self): image_man_svc = self._conn.Msvm_ImageManagementService()[0] return image_man_svc.ResizeVirtualHardDisk
**** CubicPower OpenStack Study **** def get_internal_vhd_size_by_file_size(self, vhd_path, new_vhd_file_size): """VHDX Size = Header (1 MB) + Log + Metadata Region + BAT + Payload Blocks Chunk size = maximum number of bytes described by a SB block = 2 ** 23 * LogicalSectorSize """ vhd_format = self.get_vhd_format(vhd_path) if vhd_format == constants.DISK_FORMAT_VHD: return super(VHDUtilsV2, self).get_internal_vhd_size_by_file_size( vhd_path, new_vhd_file_size) else: vhd_info = self.get_vhd_info(vhd_path) vhd_type = vhd_info['Type'] if vhd_type == self._VHD_TYPE_DIFFERENCING: raise vmutils.HyperVException(_("Differencing VHDX images " "are not supported")) else: try: with open(vhd_path, 'rb') as f: hs = VHDX_HEADER_SECTION_SIZE bes = VHDX_BAT_ENTRY_SIZE lss = vhd_info['LogicalSectorSize'] bs = self._get_vhdx_block_size(f) ls = self._get_vhdx_log_size(f) ms = self._get_vhdx_metadata_size_and_offset(f)[0] chunk_ratio = (1 << 23) * lss / bs size = new_vhd_file_size max_internal_size = (bs * chunk_ratio * (size - hs - ls - ms - bes - bes / chunk_ratio) / (bs * chunk_ratio + bes * chunk_ratio + bes)) return max_internal_size - (max_internal_size % bs) except IOError as ex: raise vmutils.HyperVException(_("Unable to obtain " "internal size from VHDX: " "%(vhd_path)s. Exception: " "%(ex)s") % {"vhd_path": vhd_path, "ex": ex})
**** CubicPower OpenStack Study **** def _get_vhdx_current_header_offset(self, vhdx_file): sequence_numbers = [] for offset in VHDX_HEADER_OFFSETS: vhdx_file.seek(offset + 8) sequence_numbers.append(struct.unpack(' current_header = sequence_numbers.index(max(sequence_numbers)) return VHDX_HEADER_OFFSETS[current_header]
**** CubicPower OpenStack Study **** def _get_vhdx_log_size(self, vhdx_file): current_header_offset = self._get_vhdx_current_header_offset(vhdx_file) offset = current_header_offset + VHDX_LOG_LENGTH_OFFSET vhdx_file.seek(offset) log_size = struct.unpack('
**** CubicPower OpenStack Study **** def _get_vhdx_metadata_size_and_offset(self, vhdx_file): offset = VHDX_METADATA_SIZE_OFFSET + VHDX_REGION_TABLE_OFFSET vhdx_file.seek(offset) metadata_offset = struct.unpack('
**** CubicPower OpenStack Study **** def _get_vhdx_block_size(self, vhdx_file): metadata_offset = self._get_vhdx_metadata_size_and_offset(vhdx_file)[1] offset = metadata_offset + VHDX_BS_METADATA_ENTRY_OFFSET vhdx_file.seek(offset) file_parameter_offset = struct.unpack(' vhdx_file.seek(file_parameter_offset + metadata_offset) block_size = struct.unpack('
**** CubicPower OpenStack Study **** def _get_vhd_info_xml(self, image_man_svc, vhd_path): (job_path, ret_val, vhd_info_xml) = image_man_svc.GetVirtualHardDiskSettingData(vhd_path) self._vmutils.check_ret_val(ret_val, job_path) return vhd_info_xml.encode('utf8', 'xmlcharrefreplace')
**** CubicPower OpenStack Study **** def get_vhd_info(self, vhd_path): image_man_svc = self._conn.Msvm_ImageManagementService()[0] vhd_info_xml = self._get_vhd_info_xml(image_man_svc, vhd_path) vhd_info_dict = {} et = ElementTree.fromstring(vhd_info_xml) for item in et.findall("PROPERTY"): name = item.attrib["NAME"] value_text = item.find("VALUE").text if name in ["Path", "ParentPath"]: vhd_info_dict[name] = value_text elif name in ["BlockSize", "LogicalSectorSize", "PhysicalSectorSize", "MaxInternalSize"]: vhd_info_dict[name] = long(value_text) elif name in ["Type", "Format"]: vhd_info_dict[name] = int(value_text) return vhd_info_dict
**** CubicPower OpenStack Study **** def get_best_supported_vhd_format(self): return constants.DISK_FORMAT_VHDX
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