virt-manager/virtinst/cloner.py

573 lines
18 KiB
Python

#
# Copyright 2013, 2015 Red Hat, Inc.
# Copyright(c) FUJITSU Limited 2007.
#
# Cloning a virtual machine module.
#
# This work is licensed under the GNU GPLv2 or later.
# See the COPYING file in the top-level directory.
import re
import os
import libvirt
from . import generatename
from . import progress
from . import xmlutil
from .guest import Guest
from .devices import DeviceInterface
from .devices import DeviceDisk
from .logger import log
from .devices import DeviceChannel
def _replace_vm(conn, name):
"""
Remove the existing VM with the same name if requested
"""
try:
vm = conn.lookupByName(name)
except libvirt.libvirtError:
return
try:
log.debug("Explicitly replacing guest '%s'", name)
if vm.ID() != -1:
log.debug("Destroying guest '%s'", name)
vm.destroy()
log.debug("Undefining guest '%s'", name)
vm.undefine()
except libvirt.libvirtError as e: # pragma: no cover
msg = (_("Could not remove old vm '%(vm)s': %(error)s") % {
"vm": name, "error": str(e)})
raise RuntimeError(msg) from None
def _generate_clone_name(conn, basename):
"""
If the orig name is "foo-clone", we don't want the clone to be
"foo-clone-clone", we want "foo-clone1"
"""
regex = r"-clone[1-9]*$"
match = re.search(regex, basename)
start_num = 1
force_num = False
if match:
num_match = re.search("[1-9]+$", match.group())
force_num = True
if num_match:
start_num = int(str(num_match.group())) + 1
basename = basename[:match.start()]
def cb(n):
return generatename.check_libvirt_collision(
conn.lookupByName, n)
basename = basename + "-clone"
return generatename.generate_name(basename, cb,
sep="", start_num=start_num, force_num=force_num)
def _generate_clone_disk_path(conn, origname, newname, origpath):
"""
Generate desired cloned disk path name, derived from the
original path, original VM name, and proposed new VM name
"""
if origpath is None:
return None
path = origpath
suffix = ""
# Try to split the suffix off the existing disk name. Ex.
# foobar.img -> foobar-clone.img
#
# If the suffix is greater than 7 characters, assume it isn't
# a file extension and is part of the disk name, at which point
# just stick '-clone' on the end.
if "." in origpath and len(origpath.rsplit(".", 1)[1]) <= 7:
path, suffix = origpath.rsplit(".", 1)
suffix = "." + suffix
dirname = os.path.dirname(path)
basename = os.path.basename(path)
clonebase = basename + "-clone"
if origname and basename == origname:
clonebase = newname
clonebase = os.path.join(dirname, clonebase)
def cb(p):
return DeviceDisk.path_definitely_exists(conn, p)
return generatename.generate_name(clonebase, cb, suffix=suffix)
def _lookup_vm(conn, name):
try:
return conn.lookupByName(name)
except libvirt.libvirtError:
e = ValueError(_("Domain '%s' was not found.") % str(name))
raise e from None
def _build_clone_vol_install(orig_disk, new_disk):
# We set a stub size for initial creation
# set_input_vol will overwrite it
size = .000001
sparse = False
vol_install = DeviceDisk.build_vol_install(
orig_disk.conn, os.path.basename(new_disk.get_source_path()),
new_disk.get_parent_pool(), size, sparse)
vol_install.set_input_vol(orig_disk.get_vol_object())
return vol_install
def _build_clone_disk(orig_disk, clonepath, allow_create, sparse):
conn = orig_disk.conn
device = DeviceDisk.DEVICE_DISK
if not clonepath:
device = DeviceDisk.DEVICE_CDROM
new_disk = DeviceDisk(conn)
new_disk.set_source_path(clonepath)
new_disk.device = device
if not allow_create:
new_disk.validate()
return new_disk
if new_disk.get_vol_object():
# Special case: non remote cloning of a guest using
# managed block devices: fall back to local cloning if
# we have permissions to do so. This validation check
# caused a few bug reports in a short period of time,
# so must be a common case.
if (conn.is_remote() or
new_disk.type != new_disk.TYPE_BLOCK or
not orig_disk.get_source_path() or
not os.access(orig_disk.get_source_path(), os.R_OK) or
not new_disk.get_source_path() or
not os.access(new_disk.get_source_path(), os.W_OK)):
raise RuntimeError(
_("Clone onto existing storage volume is not "
"currently supported: '%s'") % new_disk.get_source_path())
if (orig_disk.get_vol_object() and
new_disk.wants_storage_creation()):
vol_install = _build_clone_vol_install(orig_disk, new_disk)
if not sparse:
vol_install.allocation = vol_install.capacity
new_disk.set_vol_install(vol_install)
elif orig_disk.get_source_path():
new_disk.set_local_disk_to_clone(orig_disk, sparse)
new_disk.validate()
return new_disk
def _get_cloneable_msg(disk):
"""
If the disk storage is not cloneable, return a string explaining why
"""
if disk.wants_storage_creation():
return _("Disk path '%s' does not exist.") % disk.get_source_path()
if disk.type == "network":
proto = disk.source.protocol
if proto == "rbd":
# This case, rbd with managed storage, is implementable. It
# requires open coding a bunch of work in cloner, or reworking
# other disk code to add unique URIs for rbd volumes and pools
return (
_("Cloning rbd volumes is not yet supported.") +
" https://github.com/virt-manager/virt-manager/issues/177")
return _("Disk network type '%s' is not cloneable.") % proto
def _get_shareable_msg(disk):
if disk.is_empty():
return _("No storage to clone.")
if disk.read_only:
return _("Read Only")
if disk.shareable or disk.transient_shareBacking:
return _("Marked as shareable")
class _CloneDiskInfo:
"""
Class that tracks some additional information about how we want
to default handle each disk of the source VM
For any source disk there's 3 main scenarios:
* clone: Copy contents from src to dst. If dst path doesn't
exist we attempt to create it. If it exists we overwrite it
* preserve: Destination path is an existing, and no copying is performed.
* share: Original disk XML is used unchanged for the new disk
"""
_ACTION_SHARE = 1
_ACTION_CLONE = 2
_ACTION_PRESERVE = 3
def __init__(self, srcdisk):
self.disk = DeviceDisk(srcdisk.conn, parsexml=srcdisk.get_xml())
self.disk.set_backend_for_existing_path()
self.new_disk = None
self._share_msg = _get_shareable_msg(self.disk)
self._cloneable_msg = -1
self._newpath_msg = None
self._action = None
self.set_clone_requested()
if self.get_share_msg():
self.set_share_requested()
def is_clone_requested(self):
return self._action in [self._ACTION_CLONE]
def is_share_requested(self):
return self._action in [self._ACTION_SHARE]
def is_preserve_requested(self):
return self._action in [self._ACTION_PRESERVE]
def _set_action(self, action):
if action != self._action:
self._action = action
def set_clone_requested(self):
self._set_action(self._ACTION_CLONE)
def set_share_requested(self):
self._set_action(self._ACTION_SHARE)
def set_preserve_requested(self):
self._set_action(self._ACTION_PRESERVE)
def set_new_path(self, path, sparse):
allow_create = not self.is_preserve_requested()
if allow_create:
msg = self.get_cloneable_msg()
if msg:
return
try:
self.new_disk = Cloner.build_clone_disk(
self.disk, path, allow_create, sparse)
except Exception as e:
log.debug("Error setting clone path.", exc_info=True)
err = (_("Could not use path '%(path)s' for cloning: %(error)s") %
{"path": path, "error": str(e)})
self._newpath_msg = err
def get_share_msg(self):
return self._share_msg
def get_cloneable_msg(self):
if self._cloneable_msg == -1:
self._cloneable_msg = _get_cloneable_msg(self.disk)
return self._cloneable_msg
def get_newpath_msg(self):
return self._newpath_msg
def raise_error(self):
if self.is_clone_requested() and self.get_cloneable_msg():
msg = self.get_cloneable_msg()
err = _("Could not determine original disk information: %s" % msg)
raise ValueError(err)
if self.is_share_requested():
return
if self.get_newpath_msg():
msg = self.get_newpath_msg()
raise ValueError(msg)
class Cloner(object):
@staticmethod
def generate_clone_name(conn, basename):
return _generate_clone_name(conn, basename)
@staticmethod
def generate_clone_disk_path(conn, origname, newname, origpath):
return _generate_clone_disk_path(conn, origname, newname, origpath)
@staticmethod
def build_clone_disk(orig_disk, clonepath, allow_create, sparse):
return _build_clone_disk(orig_disk, clonepath, allow_create, sparse)
def __init__(self, conn, src_name=None, src_xml=None):
self.conn = conn
self._src_guest = None
self._new_guest = None
self._diskinfos = []
self._nvram_diskinfo = None
self._init_src(src_name, src_xml)
self._new_nvram_path = None
self._sparse = True
self._replace = False
self._reflink = False
#################
# Init routines #
#################
def _init_src(self, src_name, src_xml):
"""
Set up the source VM info we are cloning, from passed in VM name
or full XML
"""
if not src_xml:
dom = _lookup_vm(self.conn, src_name)
status = dom.info()[0]
if status not in [libvirt.VIR_DOMAIN_SHUTOFF]:
raise RuntimeError(_("Domain to clone must be shutoff."))
flags = libvirt.VIR_DOMAIN_XML_SECURE
src_xml = dom.XMLDesc(flags)
log.debug("Original XML:\n%s", src_xml)
self._src_guest = Guest(self.conn, parsexml=src_xml)
self._new_guest = Guest(self.conn, parsexml=src_xml)
self._init_new_guest()
# Collect disk info for every disk to determine if we will
# default to cloning or not
for disk in self._src_guest.devices.disk:
self._diskinfos.append(_CloneDiskInfo(disk))
for diskinfo in [d for d in self._diskinfos if d.is_clone_requested()]:
disk = diskinfo.disk
log.debug("Wants cloning: size=%s path=%s",
disk.get_size(), disk.get_source_path())
if self._src_guest.os.nvram:
old_nvram = DeviceDisk(self.conn)
old_nvram.set_source_path(self._new_guest.os.nvram)
self._nvram_diskinfo = _CloneDiskInfo(old_nvram)
def _init_new_guest(self):
"""
Perform the series of unconditional new VM changes we always make
"""
self._new_guest.id = None
self._new_guest.title = None
self._new_guest.uuid = None
self._new_guest.uuid = Guest.generate_uuid(self.conn)
for dev in self._new_guest.devices.graphics:
if dev.port and dev.port != -1:
log.warning(_("Setting the graphics device port to autoport, "
"in order to avoid conflicting."))
dev.port = -1
for iface in self._new_guest.devices.interface:
iface.target_dev = None
iface.macaddr = DeviceInterface.generate_mac(self.conn)
# For guest agent channel, remove a path to generate a new one with
# new guest name
for channel in self._new_guest.devices.channel:
if (channel.type == DeviceChannel.TYPE_UNIX and
channel.target_name and channel.source.path and
channel.target_name in channel.source.path):
channel.source.path = None
new_name = Cloner.generate_clone_name(self.conn, self.src_name)
log.debug("Auto-generated clone name '%s'", new_name)
self.set_clone_name(new_name)
##############
# Properties #
##############
@property
def src_name(self):
"""
The name of the original VM we are cloning
"""
return self._src_guest.name
@property
def new_guest(self):
"""
The Guest instance of the new XML we will create
"""
return self._new_guest
@property
def nvram_diskinfo(self):
return self._nvram_diskinfo
def set_clone_name(self, name):
self._new_guest.name = name
def set_clone_uuid(self, uuid):
"""
Override the new VMs generated UUId
"""
self._new_guest.uuid = uuid
def set_replace(self, val):
"""
If True, don't check for clone name collision, simply undefine
any conflicting guest.
"""
self._replace = bool(val)
def set_reflink(self, reflink):
"""
If true, use COW lightweight copy
"""
self._reflink = reflink
def set_sparse(self, flg):
"""
If True, attempt sparse allocation during cloning
"""
self._sparse = flg
def get_diskinfos(self):
"""
Return the list of _CloneDiskInfo instances
"""
return self._diskinfos[:]
def get_nonshare_diskinfos(self):
"""
Return a list of _CloneDiskInfo that are tagged for cloning
"""
return [di for di in self.get_diskinfos() if
not di.is_share_requested()]
def set_nvram_path(self, val):
"""
If the VM needs to have nvram content cloned, this overrides the
destination path
"""
self._new_nvram_path = val
######################
# Functional methods #
######################
def _prepare_nvram(self):
if not self._nvram_diskinfo:
return
new_nvram_path = self._new_nvram_path
if new_nvram_path is None:
nvram_dir = os.path.dirname(self._new_guest.os.nvram)
new_nvram_path = os.path.join(
nvram_dir, "%s_VARS.fd" % self._new_guest.name)
diskinfo = self._nvram_diskinfo
new_nvram = DeviceDisk(self.conn)
new_nvram.set_source_path(new_nvram_path)
old_nvram = DeviceDisk(self.conn)
old_nvram.set_source_path(diskinfo.disk.get_source_path())
if (diskinfo.is_clone_requested() and
new_nvram.wants_storage_creation() and
diskinfo.disk.get_vol_object()):
# We only run validation if there's some existing nvram we
# can copy. It's valid for nvram to not exist at VM define
# time, libvirt will create it for us
diskinfo.set_new_path(new_nvram_path, self._sparse)
diskinfo.raise_error()
diskinfo.new_disk.get_vol_install().reflink = self._reflink
else:
# There's no action to perform for this case, so drop it
self._nvram_diskinfo = None
self._new_guest.os.nvram = new_nvram.get_source_path()
def prepare(self):
"""
Validate and set up all parameters needed for the new (clone) VM
"""
try:
Guest.validate_name(self.conn, self._new_guest.name,
check_collision=not self._replace,
validate=False)
except ValueError as e:
msg = _("Invalid name for new guest: %s") % e
raise ValueError(msg) from None
for diskinfo in self.get_nonshare_diskinfos():
orig_disk = diskinfo.disk
if not diskinfo.new_disk:
# User didn't set a path, generate one
newpath = Cloner.generate_clone_disk_path(
self.conn, self.src_name,
self.new_guest.name,
orig_disk.get_source_path())
diskinfo.set_new_path(newpath, self._sparse)
if not diskinfo.new_disk:
# We hit an error, clients will raise it later
continue
new_disk = diskinfo.new_disk
assert new_disk
log.debug("Cloning srcpath=%s dstpath=%s",
orig_disk.get_source_path(), new_disk.get_source_path())
if self._reflink:
vol_install = new_disk.get_vol_install()
vol_install.reflink = self._reflink
for disk in self._new_guest.devices.disk:
if disk.target == orig_disk.target:
xmldisk = disk
# Change the XML
xmldisk.set_source_path(None)
xmldisk.type = new_disk.type
xmldisk.driver_name = orig_disk.driver_name
xmldisk.driver_type = orig_disk.driver_type
xmldisk.set_source_path(new_disk.get_source_path())
self._prepare_nvram()
# Save altered clone xml
diff = xmlutil.diff(self._src_guest.get_xml(),
self._new_guest.get_xml())
log.debug("Clone guest xml diff:\n%s", diff)
def start_duplicate(self, meter=None):
"""
Actually perform the duplication: cloning disks if needed and defining
the new clone xml.
"""
log.debug("Starting duplicate.")
meter = progress.ensure_meter(meter)
dom = None
try:
# Replace orig VM if required
if self._replace:
_replace_vm(self.conn, self._new_guest.name)
# Define domain early to catch any xml errors before duping storage
dom = self.conn.defineXML(self._new_guest.get_xml())
diskinfos = self.get_diskinfos()
if self._nvram_diskinfo:
diskinfos.append(self._nvram_diskinfo)
for diskinfo in diskinfos:
if not diskinfo.is_clone_requested():
continue
diskinfo.new_disk.build_storage(meter)
except Exception as e:
log.debug("Duplicate failed: %s", str(e))
if dom:
dom.undefine()
raise
log.debug("Duplicating finished.")