689 lines
26 KiB
Python
689 lines
26 KiB
Python
# Copyright (c) 2016 Red Hat, Inc
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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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"""Utility methods to manage guests migration
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"""
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from collections import deque
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from lxml import etree
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from oslo_log import log as logging
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from nova.compute import power_state
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import nova.conf
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from nova import exception
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from nova.virt import hardware
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from nova.virt.libvirt import config as vconfig
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LOG = logging.getLogger(__name__)
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CONF = nova.conf.CONF
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# TODO(berrange): hack to avoid a "import libvirt" in this file.
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# Remove this and similar hacks in guest.py, driver.py, host.py
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# etc in Ocata.
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libvirt = None
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def graphics_listen_addrs(migrate_data):
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"""Returns listen addresses of vnc/spice from a LibvirtLiveMigrateData"""
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listen_addrs = None
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if (migrate_data.obj_attr_is_set('graphics_listen_addr_vnc') or
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migrate_data.obj_attr_is_set('graphics_listen_addr_spice')):
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listen_addrs = {'vnc': None, 'spice': None}
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if migrate_data.obj_attr_is_set('graphics_listen_addr_vnc'):
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listen_addrs['vnc'] = str(migrate_data.graphics_listen_addr_vnc)
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if migrate_data.obj_attr_is_set('graphics_listen_addr_spice'):
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listen_addrs['spice'] = str(
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migrate_data.graphics_listen_addr_spice)
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return listen_addrs
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def serial_listen_addr(migrate_data):
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"""Returns listen address serial from a LibvirtLiveMigrateData"""
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listen_addr = None
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# NOTE (markus_z/dansmith): Our own from_legacy_dict() code can return
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# an object with nothing set here. That can happen based on the
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# compute RPC version pin. Until we can bump that major (which we
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# can do just before Ocata releases), we may still get a legacy
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# dict over the wire, converted to an object, and thus is may be unset
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# here.
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if migrate_data.obj_attr_is_set('serial_listen_addr'):
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# NOTE (markus_z): The value of 'serial_listen_addr' is either
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# an IP address (as string type) or None. There's no need of a
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# conversion, in fact, doing a string conversion of None leads to
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# 'None', which is an invalid (string type) value here.
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listen_addr = migrate_data.serial_listen_addr
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return listen_addr
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# TODO(sahid): remove me for Q*
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def serial_listen_ports(migrate_data):
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"""Returns ports serial from a LibvirtLiveMigrateData"""
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ports = []
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if migrate_data.obj_attr_is_set('serial_listen_ports'):
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ports = migrate_data.serial_listen_ports
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return ports
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def get_updated_guest_xml(guest, migrate_data, get_volume_config,
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get_vif_config=None):
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xml_doc = etree.fromstring(guest.get_xml_desc(dump_migratable=True))
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xml_doc = _update_graphics_xml(xml_doc, migrate_data)
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xml_doc = _update_serial_xml(xml_doc, migrate_data)
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xml_doc = _update_volume_xml(xml_doc, migrate_data, get_volume_config)
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xml_doc = _update_perf_events_xml(xml_doc, migrate_data)
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xml_doc = _update_memory_backing_xml(xml_doc, migrate_data)
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if get_vif_config is not None:
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xml_doc = _update_vif_xml(xml_doc, migrate_data, get_vif_config)
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if 'dst_numa_info' in migrate_data:
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xml_doc = _update_numa_xml(xml_doc, migrate_data)
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return etree.tostring(xml_doc, encoding='unicode')
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def _update_numa_xml(xml_doc, migrate_data):
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LOG.debug('_update_numa_xml input xml=%s',
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etree.tostring(xml_doc, encoding='unicode', pretty_print=True))
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info = migrate_data.dst_numa_info
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# NOTE(artom) cpu_pins, cell_pins and emulator_pins should always come
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# together, or not at all.
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if ('cpu_pins' in info and
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'cell_pins' in info and
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'emulator_pins' in info):
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for guest_id, host_ids in info.cpu_pins.items():
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vcpupin = xml_doc.find(
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'./cputune/vcpupin[@vcpu="%d"]' % int(guest_id))
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vcpupin.set('cpuset',
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hardware.format_cpu_spec(host_ids))
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emulatorpin = xml_doc.find('./cputune/emulatorpin')
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emulatorpin.set('cpuset',
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hardware.format_cpu_spec(info.emulator_pins))
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all_cells = []
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for guest_id, host_ids in info.cell_pins.items():
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all_cells.extend(host_ids)
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memnode = xml_doc.find(
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'./numatune/memnode[@cellid="%d"]' % int(guest_id))
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memnode.set('nodeset',
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hardware.format_cpu_spec(host_ids))
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memory = xml_doc.find('./numatune/memory')
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memory.set('nodeset', hardware.format_cpu_spec(set(all_cells)))
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if 'sched_vcpus' and 'sched_priority' in info:
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cputune = xml_doc.find('./cputune')
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# delete the old variant(s)
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for elem in cputune.findall('./vcpusched'):
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elem.getparent().remove(elem)
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# ...and create a new, shiny one
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vcpusched = vconfig.LibvirtConfigGuestCPUTuneVCPUSched()
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vcpusched.vcpus = info.sched_vcpus
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vcpusched.priority = info.sched_priority
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# TODO(stephenfin): Stop assuming scheduler type. We currently only
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# create these elements for real-time instances and 'fifo' is the only
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# scheduler policy we currently support so this is reasonably safe to
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# assume, but it's still unnecessary
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vcpusched.scheduler = 'fifo'
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cputune.append(vcpusched.format_dom())
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LOG.debug('_update_numa_xml output xml=%s',
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etree.tostring(xml_doc, encoding='unicode', pretty_print=True))
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return xml_doc
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def _update_graphics_xml(xml_doc, migrate_data):
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listen_addrs = graphics_listen_addrs(migrate_data)
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# change over listen addresses
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for dev in xml_doc.findall('./devices/graphics'):
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gr_type = dev.get('type')
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listen_tag = dev.find('listen')
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if gr_type in ('vnc', 'spice'):
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if listen_tag is not None:
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listen_tag.set('address', listen_addrs[gr_type])
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if dev.get('listen') is not None:
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dev.set('listen', listen_addrs[gr_type])
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return xml_doc
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def _update_serial_xml(xml_doc, migrate_data):
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listen_addr = serial_listen_addr(migrate_data)
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listen_ports = serial_listen_ports(migrate_data)
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def set_listen_addr_and_port(source, listen_addr, serial_listen_ports):
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# The XML nodes can be empty, which would make checks like
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# "if source.get('host'):" different to an explicit check for
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# None. That's why we have to check for None in this method.
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if source.get('host') is not None:
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source.set('host', listen_addr)
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device = source.getparent()
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target = device.find("target")
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if target is not None and source.get('service') is not None:
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port_index = int(target.get('port'))
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# NOTE (markus_z): Previous releases might not give us the
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# ports yet, that's why we have this check here.
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if len(serial_listen_ports) > port_index:
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source.set('service', str(serial_listen_ports[port_index]))
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# This updates all "LibvirtConfigGuestSerial" devices
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for source in xml_doc.findall("./devices/serial[@type='tcp']/source"):
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set_listen_addr_and_port(source, listen_addr, listen_ports)
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# This updates all "LibvirtConfigGuestConsole" devices
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for source in xml_doc.findall("./devices/console[@type='tcp']/source"):
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set_listen_addr_and_port(source, listen_addr, listen_ports)
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return xml_doc
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def _update_volume_xml(xml_doc, migrate_data, get_volume_config):
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"""Update XML using device information of destination host."""
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migrate_bdm_info = migrate_data.bdms
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# Update volume xml
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parser = etree.XMLParser(remove_blank_text=True)
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disk_nodes = xml_doc.findall('./devices/disk')
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bdm_info_by_serial = {x.serial: x for x in migrate_bdm_info}
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for pos, disk_dev in enumerate(disk_nodes):
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serial_source = disk_dev.findtext('serial')
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bdm_info = bdm_info_by_serial.get(serial_source)
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if (serial_source is None or
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not bdm_info or not bdm_info.connection_info or
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serial_source not in bdm_info_by_serial):
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continue
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conf = get_volume_config(
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bdm_info.connection_info, bdm_info.as_disk_info())
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if bdm_info.obj_attr_is_set('encryption_secret_uuid'):
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conf.encryption = vconfig.LibvirtConfigGuestDiskEncryption()
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conf.encryption.format = 'luks'
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secret = vconfig.LibvirtConfigGuestDiskEncryptionSecret()
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secret.type = 'passphrase'
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secret.uuid = bdm_info.encryption_secret_uuid
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conf.encryption.secret = secret
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xml_doc2 = etree.XML(conf.to_xml(), parser)
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serial_dest = xml_doc2.findtext('serial')
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# Compare source serial and destination serial number.
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# If these serial numbers match, continue the process.
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if (serial_dest and (serial_source == serial_dest)):
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LOG.debug("Find same serial number: pos=%(pos)s, "
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"serial=%(num)s",
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{'pos': pos, 'num': serial_source})
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for cnt, item_src in enumerate(disk_dev):
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# If source and destination have same item, update
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# the item using destination value.
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for item_dst in xml_doc2.findall(item_src.tag):
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if item_dst.tag != 'address':
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# hw address presented to guest must never change,
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# especially during live migration as it can be fatal
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disk_dev.remove(item_src)
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item_dst.tail = None
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disk_dev.insert(cnt, item_dst)
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# If destination has additional items, thses items should be
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# added here.
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for item_dst in list(xml_doc2):
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if item_dst.tag != 'address':
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# again, hw address presented to guest must never change
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item_dst.tail = None
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disk_dev.insert(cnt, item_dst)
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return xml_doc
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def _update_perf_events_xml(xml_doc, migrate_data):
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"""Update XML by the supported events of destination host."""
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supported_perf_events = []
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old_xml_has_perf = True
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if 'supported_perf_events' in migrate_data:
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supported_perf_events = migrate_data.supported_perf_events
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perf_events = xml_doc.findall('./perf')
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# remove perf events from xml
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if not perf_events:
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perf_events = etree.Element("perf")
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old_xml_has_perf = False
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else:
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perf_events = perf_events[0]
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for _, event in enumerate(perf_events):
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perf_events.remove(event)
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if not supported_perf_events:
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return xml_doc
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# add supported perf events
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for e in supported_perf_events:
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new_event = etree.Element("event", enabled="yes", name=e)
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perf_events.append(new_event)
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if not old_xml_has_perf:
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xml_doc.append(perf_events)
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return xml_doc
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def _update_memory_backing_xml(xml_doc, migrate_data):
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"""Update libvirt domain XML for file-backed memory
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If incoming XML has a memoryBacking element, remove access, source,
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and allocation children elements to get it to a known consistent state.
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If no incoming memoryBacking element, create one.
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If destination wants file-backed memory, add source, access,
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and allocation children.
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"""
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old_xml_has_memory_backing = True
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file_backed = False
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discard = False
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memory_backing = xml_doc.findall('./memoryBacking')
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if 'dst_wants_file_backed_memory' in migrate_data:
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file_backed = migrate_data.dst_wants_file_backed_memory
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if 'file_backed_memory_discard' in migrate_data:
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discard = migrate_data.file_backed_memory_discard
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if not memory_backing:
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# Create memoryBacking element
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memory_backing = etree.Element("memoryBacking")
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old_xml_has_memory_backing = False
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else:
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memory_backing = memory_backing[0]
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# Remove existing file-backed memory tags, if they exist.
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for name in ("access", "source", "allocation", "discard"):
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tag = memory_backing.findall(name)
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if tag:
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memory_backing.remove(tag[0])
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# Leave empty memoryBacking element
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if not file_backed:
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return xml_doc
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# Add file_backed memoryBacking children
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memory_backing.append(etree.Element("source", type="file"))
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memory_backing.append(etree.Element("access", mode="shared"))
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memory_backing.append(etree.Element("allocation", mode="immediate"))
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if discard:
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memory_backing.append(etree.Element("discard"))
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if not old_xml_has_memory_backing:
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xml_doc.append(memory_backing)
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return xml_doc
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def _update_vif_xml(xml_doc, migrate_data, get_vif_config):
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# Loop over each interface element in the original xml and find the
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# corresponding vif based on mac and then overwrite the xml with the new
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# attributes but maintain the order of the interfaces and maintain the
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# guest pci address.
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instance_uuid = xml_doc.findtext('uuid')
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parser = etree.XMLParser(remove_blank_text=True)
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interface_nodes = xml_doc.findall('./devices/interface')
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migrate_vif_by_mac = {vif.source_vif['address']: vif
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for vif in migrate_data.vifs}
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for interface_dev in interface_nodes:
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mac = interface_dev.find('mac')
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mac = mac if mac is not None else {}
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mac_addr = mac.get('address')
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if mac_addr:
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migrate_vif = migrate_vif_by_mac[mac_addr]
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vif = migrate_vif.get_dest_vif()
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# get_vif_config is a partial function of
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# nova.virt.libvirt.vif.LibvirtGenericVIFDriver.get_config
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# with all but the 'vif' kwarg set already and returns a
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# LibvirtConfigGuestInterface object.
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vif_config = get_vif_config(vif=vif)
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else:
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# This shouldn't happen but if it does, we need to abort the
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# migration.
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raise exception.NovaException(
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'Unable to find MAC address in interface XML for '
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'instance %s: %s' % (
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instance_uuid,
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etree.tostring(interface_dev, encoding='unicode')))
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# At this point we want to replace the interface elements with the
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# destination vif config xml *except* for the guest PCI address.
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conf_xml = vif_config.to_xml()
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LOG.debug('Updating guest XML with vif config: %s', conf_xml,
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instance_uuid=instance_uuid)
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dest_interface_elem = etree.XML(conf_xml, parser)
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# Save off the hw address and MTU presented to the guest since that
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# can't change during live migration.
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address = interface_dev.find('address')
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mtu = interface_dev.find('mtu')
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# Now clear the interface's current elements and insert everything
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# from the destination vif config xml.
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interface_dev.clear()
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# Insert attributes.
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for attr_name, attr_value in dest_interface_elem.items():
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interface_dev.set(attr_name, attr_value)
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# Insert sub-elements.
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for index, dest_interface_subelem in enumerate(dest_interface_elem):
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# NOTE(mnaser): If we don't have an MTU, don't define one, else
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# the live migration will crash.
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if dest_interface_subelem.tag == 'mtu' and mtu is None:
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continue
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interface_dev.insert(index, dest_interface_subelem)
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# And finally re-insert the hw address.
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interface_dev.insert(index + 1, address)
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return xml_doc
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def find_job_type(guest, instance, logging_ok=True):
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"""Determine the (likely) current migration job type
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:param guest: a nova.virt.libvirt.guest.Guest
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:param instance: a nova.objects.Instance
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:param logging_ok: If logging in this method is OK. If called from a
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native thread then logging is generally prohibited.
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Annoyingly when job type == NONE and migration is
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no longer running, we don't know whether we stopped
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because of failure or completion. We can distinguish
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these cases by seeing if the VM still exists & is
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running on the current host
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:returns: a libvirt job type constant
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"""
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def _log(func, msg, *args, **kwargs):
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if logging_ok:
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func(msg, *args, **kwargs)
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try:
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if guest.is_active():
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_log(LOG.debug, "VM running on src, migration failed",
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instance=instance)
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return libvirt.VIR_DOMAIN_JOB_FAILED
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else:
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_log(LOG.debug, "VM is shutoff, migration finished",
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instance=instance)
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return libvirt.VIR_DOMAIN_JOB_COMPLETED
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except libvirt.libvirtError as ex:
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_log(LOG.debug, "Error checking domain status %(ex)s", {"ex": ex},
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instance=instance)
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if ex.get_error_code() == libvirt.VIR_ERR_NO_DOMAIN:
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_log(LOG.debug, "VM is missing, migration finished",
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instance=instance)
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return libvirt.VIR_DOMAIN_JOB_COMPLETED
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else:
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_log(LOG.info, "Error %(ex)s, migration failed", {"ex": ex},
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instance=instance)
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return libvirt.VIR_DOMAIN_JOB_FAILED
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def should_trigger_timeout_action(instance, elapsed, completion_timeout,
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migration_status):
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"""Determine if the migration timeout action should be triggered
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:param instance: a nova.objects.Instance
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:param elapsed: total elapsed time of migration in secs
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:param completion_timeout: time in secs to allow for completion
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:param migration_status: current status of the migration
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Check the completion timeout to determine if it has been hit,
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and should thus cause migration timeout action to be triggered.
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Avoid migration to be aborted or triggered post-copy again if it is
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running in post-copy mode
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:returns: True if the migration completion timeout action should be
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performed, False otherwise
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"""
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if not completion_timeout:
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return False
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if migration_status == 'running (post-copy)':
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return False
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|
|
if elapsed > completion_timeout:
|
|
LOG.warning("Live migration not completed after %d sec",
|
|
completion_timeout, instance=instance)
|
|
return True
|
|
|
|
return False
|
|
|
|
|
|
def update_downtime(guest, instance,
|
|
olddowntime,
|
|
downtime_steps, elapsed):
|
|
"""Update max downtime if needed
|
|
|
|
:param guest: a nova.virt.libvirt.guest.Guest to set downtime for
|
|
:param instance: a nova.objects.Instance
|
|
:param olddowntime: current set downtime, or None
|
|
:param downtime_steps: list of downtime steps
|
|
:param elapsed: total time of migration in secs
|
|
|
|
Determine if the maximum downtime needs to be increased
|
|
based on the downtime steps. Each element in the downtime
|
|
steps list should be a 2 element tuple. The first element
|
|
contains a time marker and the second element contains
|
|
the downtime value to set when the marker is hit.
|
|
|
|
The guest object will be used to change the current
|
|
downtime value on the instance.
|
|
|
|
Any errors hit when updating downtime will be ignored
|
|
|
|
:returns: the new downtime value
|
|
"""
|
|
LOG.debug("Current %(dt)s elapsed %(elapsed)d steps %(steps)s",
|
|
{"dt": olddowntime, "elapsed": elapsed,
|
|
"steps": downtime_steps}, instance=instance)
|
|
thisstep = None
|
|
for step in downtime_steps:
|
|
if elapsed > step[0]:
|
|
thisstep = step
|
|
|
|
if thisstep is None:
|
|
LOG.debug("No current step", instance=instance)
|
|
return olddowntime
|
|
|
|
if thisstep[1] == olddowntime:
|
|
LOG.debug("Downtime does not need to change",
|
|
instance=instance)
|
|
return olddowntime
|
|
|
|
LOG.info("Increasing downtime to %(downtime)d ms "
|
|
"after %(waittime)d sec elapsed time",
|
|
{"downtime": thisstep[1],
|
|
"waittime": thisstep[0]},
|
|
instance=instance)
|
|
|
|
try:
|
|
guest.migrate_configure_max_downtime(thisstep[1])
|
|
except libvirt.libvirtError as e:
|
|
LOG.warning("Unable to increase max downtime to %(time)d ms: %(e)s",
|
|
{"time": thisstep[1], "e": e}, instance=instance)
|
|
return thisstep[1]
|
|
|
|
|
|
def save_stats(instance, migration, info, remaining):
|
|
"""Save migration stats to the database
|
|
|
|
:param instance: a nova.objects.Instance
|
|
:param migration: a nova.objects.Migration
|
|
:param info: a nova.virt.libvirt.guest.JobInfo
|
|
:param remaining: percentage data remaining to transfer
|
|
|
|
Update the migration and instance objects with
|
|
the latest available migration stats
|
|
"""
|
|
|
|
# The fully detailed stats
|
|
migration.memory_total = info.memory_total
|
|
migration.memory_processed = info.memory_processed
|
|
migration.memory_remaining = info.memory_remaining
|
|
migration.disk_total = info.disk_total
|
|
migration.disk_processed = info.disk_processed
|
|
migration.disk_remaining = info.disk_remaining
|
|
migration.save()
|
|
|
|
# The coarse % completion stats
|
|
instance.progress = 100 - remaining
|
|
instance.save()
|
|
|
|
|
|
def trigger_postcopy_switch(guest, instance, migration):
|
|
try:
|
|
guest.migrate_start_postcopy()
|
|
except libvirt.libvirtError as e:
|
|
LOG.warning("Failed to switch to post-copy live migration: %s",
|
|
e, instance=instance)
|
|
else:
|
|
# NOTE(ltomas): Change the migration status to indicate that
|
|
# it is in post-copy active mode, i.e., the VM at
|
|
# destination is the active one
|
|
LOG.info("Switching to post-copy migration mode",
|
|
instance=instance)
|
|
migration.status = 'running (post-copy)'
|
|
migration.save()
|
|
|
|
|
|
def run_tasks(guest, instance, active_migrations, on_migration_failure,
|
|
migration, is_post_copy_enabled):
|
|
"""Run any pending migration tasks
|
|
|
|
:param guest: a nova.virt.libvirt.guest.Guest
|
|
:param instance: a nova.objects.Instance
|
|
:param active_migrations: dict of active migrations
|
|
:param on_migration_failure: queue of recovery tasks
|
|
:param migration: a nova.objects.Migration
|
|
:param is_post_copy_enabled: True if post-copy can be used
|
|
|
|
Run any pending migration tasks queued against the
|
|
provided instance object. The active migrations dict
|
|
should use instance UUIDs for keys and a queue of
|
|
tasks as the values.
|
|
|
|
Currently the valid tasks that can be requested
|
|
are "pause" and "force-complete". Other tasks will
|
|
be ignored.
|
|
"""
|
|
|
|
tasks = active_migrations.get(instance.uuid, deque())
|
|
while tasks:
|
|
task = tasks.popleft()
|
|
if task == 'force-complete':
|
|
if migration.status == 'running (post-copy)':
|
|
LOG.warning("Live-migration %s already switched "
|
|
"to post-copy mode.",
|
|
instance=instance)
|
|
elif is_post_copy_enabled:
|
|
trigger_postcopy_switch(guest, instance, migration)
|
|
else:
|
|
try:
|
|
guest.pause()
|
|
on_migration_failure.append("unpause")
|
|
except Exception as e:
|
|
LOG.warning("Failed to pause instance during "
|
|
"live-migration %s",
|
|
e, instance=instance)
|
|
else:
|
|
LOG.warning("Unknown migration task '%(task)s'",
|
|
{"task": task}, instance=instance)
|
|
|
|
|
|
def run_recover_tasks(host, guest, instance, on_migration_failure):
|
|
"""Run any pending migration recovery tasks
|
|
|
|
:param host: a nova.virt.libvirt.host.Host
|
|
:param guest: a nova.virt.libvirt.guest.Guest
|
|
:param instance: a nova.objects.Instance
|
|
:param on_migration_failure: queue of recovery tasks
|
|
|
|
Run any recovery tasks provided in the on_migration_failure
|
|
queue.
|
|
|
|
Currently the only valid task that can be requested
|
|
is "unpause". Other tasks will be ignored
|
|
"""
|
|
|
|
while on_migration_failure:
|
|
task = on_migration_failure.popleft()
|
|
# NOTE(tdurakov): there is still possibility to leave
|
|
# instance paused in case of live-migration failure.
|
|
# This check guarantee that instance will be resumed
|
|
# in this case
|
|
if task == 'unpause':
|
|
try:
|
|
state = guest.get_power_state(host)
|
|
if state == power_state.PAUSED:
|
|
guest.resume()
|
|
except Exception as e:
|
|
LOG.warning("Failed to resume paused instance "
|
|
"before live-migration rollback %s",
|
|
e, instance=instance)
|
|
else:
|
|
LOG.warning("Unknown migration task '%(task)s'",
|
|
{"task": task}, instance=instance)
|
|
|
|
|
|
def downtime_steps(data_gb):
|
|
'''Calculate downtime value steps and time between increases.
|
|
|
|
:param data_gb: total GB of RAM and disk to transfer
|
|
|
|
This looks at the total downtime steps and upper bound
|
|
downtime value and uses a linear function.
|
|
|
|
For example, with 10 steps, 30 second step delay, 3 GB
|
|
of RAM and 400ms target maximum downtime, the downtime will
|
|
be increased every 90 seconds in the following progression:
|
|
|
|
- 0 seconds -> set downtime to 40ms
|
|
- 90 seconds -> set downtime to 76ms
|
|
- 180 seconds -> set downtime to 112ms
|
|
- 270 seconds -> set downtime to 148ms
|
|
- 360 seconds -> set downtime to 184ms
|
|
- 450 seconds -> set downtime to 220ms
|
|
- 540 seconds -> set downtime to 256ms
|
|
- 630 seconds -> set downtime to 292ms
|
|
- 720 seconds -> set downtime to 328ms
|
|
- 810 seconds -> set downtime to 364ms
|
|
- 900 seconds -> set downtime to 400ms
|
|
|
|
This allows the guest a good chance to complete migration
|
|
with a small downtime value.
|
|
'''
|
|
downtime = CONF.libvirt.live_migration_downtime
|
|
steps = CONF.libvirt.live_migration_downtime_steps
|
|
delay = CONF.libvirt.live_migration_downtime_delay
|
|
|
|
delay = int(delay * data_gb)
|
|
|
|
base = downtime / steps
|
|
offset = (downtime - base) / steps
|
|
|
|
for i in range(steps + 1):
|
|
yield (int(delay * i), int(base + offset * i))
|