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@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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