[Kimchi-devel] [PATCH 7/8] Clone virtual machines
Aline Manera
alinefm at linux.vnet.ibm.com
Tue Nov 4 11:13:04 UTC 2014
On 11/04/2014 09:07 AM, Aline Manera wrote:
>
> On 11/02/2014 11:05 PM, Crístian Viana wrote:
>> The new command "POST /vms/<vm-name>/clone" will create a new virtual
>> machine based on <vm-name>. The new VM will have the exact same
>> settings, except the name, UUID, MAC address and disk paths; those
>> values will be generated automatically.
>>
>> Signed-off-by: Crístian Viana <vianac at linux.vnet.ibm.com>
>> ---
>> docs/API.md | 7 ++
>> src/kimchi/control/vms.py | 1 +
>> src/kimchi/i18n.py | 2 +
>> src/kimchi/model/vms.py | 297
>> +++++++++++++++++++++++++++++++++++++++++++++-
>> 4 files changed, 305 insertions(+), 2 deletions(-)
>>
>> diff --git a/docs/API.md b/docs/API.md
>> index 29ae4e1..d5f8df6 100644
>> --- a/docs/API.md
>> +++ b/docs/API.md
>> @@ -133,6 +133,13 @@ the following general conventions:
>> risk of data loss caused by reset without the guest OS
>> shutdown.
>> * connect: Prepare the connection for spice or vnc
>> +* clone: Create a new VM identical to this VM. The new VM's name,
>> UUID and
>> + network MAC addresses will be generated automatically. Each
>> existing
>> + disks will be copied to a new volume in the same storage
>> pool. If
>> + there is no available space on that storage pool to hold
>> the new
>> + volume, it will be created on the pool 'default'. This
>> action returns
>> + a Task.
>> +
>> ### Sub-resource: Virtual Machine Screenshot
>> **URI:** /vms/*:name*/screenshot
>> diff --git a/src/kimchi/control/vms.py b/src/kimchi/control/vms.py
>> index 88d8a81..a1589ef 100644
>> --- a/src/kimchi/control/vms.py
>> +++ b/src/kimchi/control/vms.py
>> @@ -46,6 +46,7 @@ class VM(Resource):
>> self.shutdown = self.generate_action_handler('shutdown')
>> self.reset = self.generate_action_handler('reset')
>> self.connect = self.generate_action_handler('connect')
>> + self.clone = self.generate_action_handler_task('clone')
>> @property
>> def data(self):
>> diff --git a/src/kimchi/i18n.py b/src/kimchi/i18n.py
>> index 712e5a6..304c870 100644
>> --- a/src/kimchi/i18n.py
>> +++ b/src/kimchi/i18n.py
>> @@ -102,6 +102,8 @@ messages = {
>> "KCHVM0030E": _("Unable to get access metadata of virtual
>> machine %(name)s. Details: %(err)s"),
>> "KCHVM0031E": _("The guest console password must be a string."),
>> "KCHVM0032E": _("The life time for the guest console password
>> must be a number."),
>> + "KCHVM0033E": _("Virtual machine '%(name)s' must be stopped
>> before cloning it."),
>> + "KCHVM0034E": _("Insufficient disk space to clone virtual
>> machine '%(name)s'"),
>> "KCHVMHDEV0001E": _("VM %(vmid)s does not contain directly
>> assigned host device %(dev_name)s."),
>> "KCHVMHDEV0002E": _("The host device %(dev_name)s is not
>> allowed to directly assign to VM."),
>> diff --git a/src/kimchi/model/vms.py b/src/kimchi/model/vms.py
>> index f2e4ae3..17fe2f4 100644
>> --- a/src/kimchi/model/vms.py
>> +++ b/src/kimchi/model/vms.py
>> @@ -22,6 +22,7 @@ import lxml.etree as ET
>> from lxml import etree, objectify
>> import os
>> import random
>> +import re
>> import string
>> import time
>> import uuid
>> @@ -30,17 +31,20 @@ from xml.etree import ElementTree
>> import libvirt
>> from cherrypy.process.plugins import BackgroundTask
>> -from kimchi import vnc
>> +from kimchi import model, vnc
>> from kimchi.config import READONLY_POOL_TYPE
>> from kimchi.exception import InvalidOperation, InvalidParameter
>> from kimchi.exception import NotFoundError, OperationFailed
>> from kimchi.model.config import CapabilitiesModel
>> +from kimchi.model.tasks import TaskModel
>> from kimchi.model.templates import TemplateModel
>> from kimchi.model.utils import get_vm_name
>> from kimchi.model.utils import get_metadata_node
>> from kimchi.model.utils import set_metadata_node
>> +from kimchi.rollbackcontext import RollbackContext
>> from kimchi.screenshot import VMScreenshot
>> -from kimchi.utils import import_class, kimchi_log, run_setfacl_set_attr
>> +from kimchi.utils import add_task, import_class, kimchi_log
>> +from kimchi.utils import run_setfacl_set_attr
>> from kimchi.utils import template_name_from_uri
>> from kimchi.xmlutils.utils import xpath_get_text, xml_item_update
>> @@ -63,6 +67,15 @@ VM_LIVE_UPDATE_PARAMS = {}
>> stats = {}
>> +XPATH_DOMAIN_DISK =
>> "/domain/devices/disk[@device='disk']/source/@file"
>> +XPATH_DOMAIN_DISK_BY_FILE =
>> "./devices/disk[@device='disk']/source[@file='%s']"
>> +XPATH_DOMAIN_NAME = '/domain/name'
>> +XPATH_DOMAIN_MAC =
>> "/domain/devices/interface[@type='network']/mac/@address"
>> +XPATH_DOMAIN_MAC_BY_ADDRESS = "./devices/interface[@type='network']/"\
>> + "mac[@address='%s']"
>> +XPATH_DOMAIN_UUID = '/domain/uuid'
>> +
>> +
>> class VMsModel(object):
>> def __init__(self, **kargs):
>> self.conn = kargs['conn']
>> @@ -251,6 +264,11 @@ class VMModel(object):
>> self.vmscreenshot = VMScreenshotModel(**kargs)
>> self.users =
>> import_class('kimchi.model.host.UsersModel')(**kargs)
>> self.groups =
>> import_class('kimchi.model.host.GroupsModel')(**kargs)
>> + self.vms = VMsModel(**kargs)
>> + self.task = TaskModel(**kargs)
>> + self.storagepool = model.storagepools.StoragePoolModel(**kargs)
>> + self.storagevolume =
>> model.storagevolumes.StorageVolumeModel(**kargs)
>> + self.storagevolumes =
>> model.storagevolumes.StorageVolumesModel(**kargs)
>> def update(self, name, params):
>> dom = self.get_vm(name, self.conn)
>> @@ -258,6 +276,281 @@ class VMModel(object):
>> self._live_vm_update(dom, params)
>> return dom.name().decode('utf-8')
>> + def clone(self, name):
>> + """Clone a virtual machine based on an existing one.
>> +
>> + The new virtual machine will have the exact same
>> configuration as the
>> + original VM, except for the name, UUID, MAC addresses and
>> disks. The
>> + name will have the form "<name>-clone-<number>", with
>> <number> starting
>> + at 1; the UUID will be generated randomly; the MAC addresses
>> will be
>> + generated randomly with no conflicts within the original and
>> the new
>> + VM; and the disks will be new volumes [mostly] on the same
>> storage
>> + pool, with the same content as the original disks. The
>> storage pool
>> + 'default' will always be used when cloning SCSI and iSCSI
>> disks and
>> + when the original storage pool cannot hold the new volume.
>> +
>> + An exception will be raised if the virtual machine <name> is
>> not
>> + shutoff, if there is no available space to copy a new volume
>> to the
>> + storage pool 'default' (when there was also no space to copy
>> it to the
>> + original storage pool) and if one of the virtual machine's
>> disks belong
>> + to a storage pool not supported by Kimchi.
>> +
>> + Parameters:
>> + name -- The name of the existing virtual machine to be cloned.
>> +
>> + Return:
>> + A Task running the clone operation.
>> + """
>> + name = name.decode('utf-8')
>> +
>> + # VM must be shutoff in order to clone it
>> + info = self.lookup(name)
>> + if info['state'] != u'shutoff':
>> + raise InvalidParameter('KCHVM0033E', {'name': name})
>> +
>> + # this name will be used as the Task's 'target_uri' so it
>> needs to be
>> + # defined now.
>> + new_name = self._clone_get_next_name(name)
>> +
>> + # create a task with the actual clone function
>> + taskid = add_task(u'/vms/%s' % new_name, self._clone_task,
>> + self.objstore,
>> + {'name': name, 'new_name': new_name})
>> +
>> + return self.task.lookup(taskid)
>> +
>> + def _clone_task(self, cb, params):
>> + """Asynchronous function which performs the clone operation.
>> +
>> + Parameters:
>> + cb -- A callback function to signal the Task's progress.
>> + params -- A dict with the following values:
>> + "name": the name of the original VM.
>> + "new_name": the name of the new VM.
>> + """
>> + name = params['name']
>> + new_name = params['new_name']
>> + vir_conn = self.conn.get()
>> +
>> + # fetch base XML
>> + cb('reading source VM XML')
>> + vir_dom = vir_conn.lookupByName(name)
>> + xml =
>> vir_dom.XMLDesc(libvirt.VIR_DOMAIN_XML_SECURE).decode('utf-8')
>> +
>> + # update name
>> + cb('updating VM name')
>> + xml = xml_item_update(xml, './name', new_name)
>> +
>> + # update UUID
>> + cb('updating VM UUID')
>> + new_uuid = unicode(uuid.uuid4())
>> + xml = xml_item_update(xml, './uuid', new_uuid)
>> +
>> + # update MAC addresses
>> + cb('updating VM MAC addresses')
>> + xml = self._clone_update_mac_addresses(xml)
>> +
>> + with RollbackContext() as rollback:
>> + # copy disks
>> + cb('copying VM disks')
>> + xml = self._clone_update_disks(xml, rollback)
>> +
>> + # update objstore entry
>> + cb('updating object store')
>> + self._clone_update_objstore(vir_dom, new_uuid, rollback)
>> +
>> + # create new guest
>> + cb('defining new VM')
>> + vir_conn.defineXML(xml)
>> +
>> + rollback.commitAll()
>> +
>> + cb('OK', True)
>> +
>> + def _clone_get_next_name(self, basename):
>> + """Find the next available name for a clone VM.
>> +
>> + If any VM named "<basename>-clone-<number>" is found, use
>> + the maximum "number" + 1; else, use 1.
>> +
>> + Argument:
>> + basename -- the name of the original VM.
>> +
>> + Return:
>> + A UTF-8 string in the format "<basename>-clone-<number>".
>> + """
>> + re_group_num = 'num'
>> +
>> + max_num = 0
>> + re_cloned_vm = re.compile(u'%s-clone-(?P<%s>\d+)' %
>> + (basename, re_group_num))
>> +
>> + vm_names = self.vms.get_list()
>> +
>> + for v in vm_names:
>> + match = re_cloned_vm.match(v)
>> + if match is not None:
>> + max_num = max(max_num, int(match.group(re_group_num)))
>> +
>> + # increments the maximum "clone number" found
>> + return u'%s-clone-%d' % (basename, max_num + 1)
>> +
>> + @staticmethod
>> + def _clone_update_mac_addresses(xml):
>> + """Update the MAC addresses with new values in the XML
>> descriptor of a
>> + cloning domain.
>> +
>> + The new MAC addresses will be generated randomly, and their
>> values are
>> + guaranteed to be distinct from the ones in the original VM.
>> +
>> + Arguments:
>> + xml -- The XML descriptor of the original domain.
>> +
>> + Return:
>> + The XML descriptor <xml> with the new MAC addresses instead
>> of the
>> + old ones.
>> + """
>> + old_macs = xpath_get_text(xml, XPATH_DOMAIN_MAC)
>> + new_macs = []
>> +
>> + for mac in old_macs:
>> + while True:
>> + new_mac = model.vmifaces.VMIfacesModel.random_mac()
>> + # make sure the new MAC doesn't conflict with the
>> original VM
>> + # and with the new values on the new VM.
>> + if new_mac not in (old_macs + new_macs):
>> + new_macs.append(new_mac)
>> + break
>> +
>> + xml = xml_item_update(xml, XPATH_DOMAIN_MAC_BY_ADDRESS %
>> mac,
>> + new_mac, 'address')
>> +
>> + return xml
>> +
>> + def _clone_update_disks(self, xml, rollback):
>> + """Clone disks from a virtual machine. The disks are copied
>> as new
>> + volumes and the new VM's XML is updated accordingly.
>> +
>> + Arguments:
>> + xml -- The XML descriptor of the original VM + new values for
>> + "/domain/name" and "/domain/uuid".
>> + rollback -- A rollback context so the new volumes can be
>> removed if an
>> + error occurs during the cloning operation.
>> +
>> + Return:
>> + The XML descriptor <xml> with the new disk paths instead of the
>> + old ones.
>> + """
>> + # the UUID will be used to create the disk paths
>> + uuid = xpath_get_text(xml, XPATH_DOMAIN_UUID)[0]
>> + all_paths = xpath_get_text(xml, XPATH_DOMAIN_DISK)
>> +
>> + vir_conn = self.conn.get()
>> +
>
>> + for i, path in enumerate(all_paths):
>> + vir_orig_vol = vir_conn.storageVolLookupByPath(path)
>> + vir_pool = vir_orig_vol.storagePoolLookupByVolume()
>> +
>
> I've just thought about the case the disk is not in a pool.
> For example, we allow user create a Template (and then a VM) using an
> Image file. That image file is not necessarily on a pool. ie, it is a
> volume from libvirt perspective.
it is *NOT* a volume from libvirt perspective
> So in that case the call vir_conn.storageVolLookupByPath(path) will
> raise an exception and stop the clone operation.
> We need to have this scenario in mind and work with it properly.
>
>
>> + orig_pool_name = vir_pool.name().decode('utf-8')
>> + orig_vol_name = vir_orig_vol.name().decode('utf-8')
>> +
>> + orig_pool = self.storagepool.lookup(orig_pool_name)
>> + orig_vol = self.storagevolume.lookup(orig_pool_name,
>> orig_vol_name)
>> +
>> + new_pool_name = orig_pool_name
>> + new_pool = orig_pool
>> +
>> + if orig_pool['type'] in ['dir', 'netfs', 'logical']:
>> + # if a volume in a pool 'dir', 'netfs' or 'logical'
>> cannot hold
>> + # a new volume with the same size, the pool
>> 'default' should
>> + # be used
>> + if orig_vol['capacity'] > orig_pool['available']:
>> + kimchi_log.warning('storage pool \'%s\' doesn\'t
>> have '
>> + 'enough free space to store
>> image '
>> + '\'%s\'; falling back to
>> \'default\'',
>> + orig_pool_name, path)
>> + new_pool_name = u'default'
>> + new_pool = self.storagepool.lookup(u'default')
>> +
>> + # ...and if even the pool 'default' cannot hold
>> a new
>> + # volume, raise an exception
>> + if orig_vol['capacity'] > new_pool['available']:
>> + domain_name = xpath_get_text(xml,
>> XPATH_DOMAIN_NAME)[0]
>> + raise InvalidOperation('KCHVM0034E',
>> + {'name': domain_name})
>> +
>> + elif orig_pool['type'] in ['scsi', 'iscsi']:
>> + # SCSI and iSCSI always fall back to the storage
>> pool 'default'
>> + kimchi_log.warning('cannot create new volume for
>> clone in '
>> + 'storage pool \'%s\'; falling
>> back to '
>> + '\'default\'', orig_pool_name)
>> + new_pool_name = u'default'
>> + new_pool = self.storagepool.lookup(u'default')
>> +
>> + # if the pool 'default' cannot hold a new volume, raise
>> + # an exception
>> + if orig_vol['capacity'] > new_pool['available']:
>> + domain_name = xpath_get_text(xml,
>> XPATH_DOMAIN_NAME)[0]
>> + raise InvalidOperation('KCHVM0034E', {'name':
>> domain_name})
>> +
>> + else:
>> + # unexpected storage pool type
>> + raise InvalidOperation('KCHPOOL0014E',
>> + {'type': orig_pool['type']})
>> +
>> + # new volume name: <UUID>-<loop-index>.<original extension>
>> + # e.g. 1234-5678-9012-3456-0.img
>> + ext = os.path.splitext(path)[1]
>> + new_vol_name = u'%s-%d%s' % (uuid, i, ext)
>> + new_vol_params = {'name': new_vol_name, 'volume_path':
>> path}
>> + task = self.storagevolumes.create(new_pool_name,
>> new_vol_params)
>> + self.task.wait(task['id'], 3600) # 1 h
>> +
>> + # get the new volume path and update the XML descriptor
>> + new_vol = self.storagevolume.lookup(new_pool_name,
>> new_vol_name)
>> + xml = xml_item_update(xml, XPATH_DOMAIN_DISK_BY_FILE %
>> path,
>> + new_vol['path'], 'file')
>> +
>> + # remove the new volume should an error occur later
>> + rollback.prependDefer(self.storagevolume.delete,
>> new_pool_name,
>> + new_vol_name)
>> +
>> + return xml
>> +
>> + def _clone_update_objstore(self, dom, new_uuid, rollback):
>> + """Update Kimchi's object store with the cloning VM.
>> +
>> + Arguments:
>> + dom -- The native domain object of the original VM.
>> + new_uuid -- The UUID of the new, clonning VM.
>> + rollback -- A rollback context so the object store entry can
>> be removed
>> + if an error occurs during the cloning operation.
>> + """
>> + xml =
>> dom.XMLDesc(libvirt.VIR_DOMAIN_XML_SECURE).decode('utf-8')
>> + old_uuid = xpath_get_text(xml, XPATH_DOMAIN_UUID)[0]
>> +
>> + with self.objstore as session:
>> + try:
>> + vm = session.get('vm', old_uuid)
>> + icon = vm['icon']
>> + session.store('vm', new_uuid, {'icon': icon})
>> + except NotFoundError:
>> + # if we cannot find an object store entry for the
>> original VM,
>> + # don't store one with an empty value.
>> + pass
>> + else:
>> + # we need to define a custom function to prepend to the
>> + # rollback context because the object store session
>> needs to be
>> + # opened and closed correctly (i.e. "prependDefer" only
>> + # accepts one command at a time but we need more
>> than one to
>> + # handle an object store).
>> + def _rollback_objstore():
>> + with self.objstore as session_rb:
>> + session_rb.delete('vm', new_uuid,
>> ignore_missing=True)
>> +
>> + # remove the new object store entry should an error
>> occur later
>> + rollback.prependDefer(_rollback_objstore)
>> +
>> def _build_access_elem(self, users, groups):
>> access = E.access()
>> for user in users:
>
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