instance.py

from __future__ import absolute_import, unicode_literals
from datetime import timedelta
from logging import getLogger
from importlib import import_module
import string

import django.conf
from django.db.models import (BooleanField, CharField, DateTimeField,
                              IntegerField, ForeignKey, Manager,
                              ManyToManyField, permalink, TextField)
from django.contrib.auth.models import User
from django.core import signing
from django.dispatch import Signal
from django.utils import timezone
from django.utils.translation import ugettext_lazy as _

from model_utils.models import TimeStampedModel
from taggit.managers import TaggableManager

from acl.models import AclBase
from storage.models import Disk
from ..tasks import local_tasks, vm_tasks, agent_tasks
from .activity import instance_activity
from .common import BaseResourceConfigModel, Lease
from .network import Interface
from .node import Node, Trait
from django.core.exceptions import PermissionDenied

logger = getLogger(__name__)
pre_state_changed = Signal(providing_args=["new_state"])
post_state_changed = Signal(providing_args=["new_state"])
pwgen = User.objects.make_random_password
scheduler = import_module(name=django.conf.settings.VM_SCHEDULER)

ACCESS_PROTOCOLS = django.conf.settings.VM_ACCESS_PROTOCOLS
ACCESS_METHODS = [(key, name) for key, (name, port, transport)
                  in ACCESS_PROTOCOLS.iteritems()]
VNC_PORT_RANGE = (2000, 65536)  # inclusive start, exclusive end


def find_unused_vnc_port():
    used = set(Instance.objects.values_list('vnc_port', flat=True))
    for p in xrange(*VNC_PORT_RANGE):
        if p not in used:
            return p
    else:
        raise Exception("No unused port could be found for VNC.")


class InstanceActiveManager(Manager):

    def get_query_set(self):
        return super(InstanceActiveManager,
                     self).get_query_set().filter(destroyed=None)


class VirtualMachineDescModel(BaseResourceConfigModel):

    """Abstract base for virtual machine describing models.
    """
    access_method = CharField(max_length=10, choices=ACCESS_METHODS,
                              verbose_name=_('access method'),
                              help_text=_('Primary remote access method.'))
    boot_menu = BooleanField(verbose_name=_('boot menu'), default=False,
                             help_text=_(
                                 'Show boot device selection menu on boot.'))
    lease = ForeignKey(Lease, help_text=_("Preferred expiration periods."))
    raw_data = TextField(verbose_name=_('raw_data'), blank=True, help_text=_(
        'Additional libvirt domain parameters in XML format.'))
    req_traits = ManyToManyField(Trait, blank=True,
                                 help_text=_("A set of traits required for a "
                                             "node to declare to be suitable "
                                             "for hosting the VM."),
                                 verbose_name=_("required traits"))
    tags = TaggableManager(blank=True, verbose_name=_("tags"))

    class Meta:
        abstract = True


class InstanceTemplate(AclBase, VirtualMachineDescModel, TimeStampedModel):

    """Virtual machine template.

    Every template has:
      * a name and a description
      * an optional parent template
      * state of the template
      * an OS name/description
      * a method of access to the system
      * default values of base resource configuration
      * list of attached images
      * set of interfaces
      * lease times (suspension & deletion)
      * time of creation and last modification
    """
    ACL_LEVELS = (
        ('user', _('user')),          # see all details
        ('operator', _('operator')),
        ('owner', _('owner')),        # superuser, can delete, delegate perms
    )
    STATES = [('NEW', _('new')),        # template has just been created
              ('SAVING', _('saving')),  # changes are being saved
              ('READY', _('ready'))]    # template is ready for instantiation
    name = CharField(max_length=100, unique=True,
                     verbose_name=_('name'),
                     help_text=_('Human readable name of template.'))
    description = TextField(verbose_name=_('description'), blank=True)
    parent = ForeignKey('self', null=True, blank=True,
                        verbose_name=_('parent template'),
                        help_text=_('Template which this one is derived of.'))
    system = TextField(verbose_name=_('operating system'),
                       blank=True,
                       help_text=(_('Name of operating system in '
                                    'format like "%s".') %
                                  'Ubuntu 12.04 LTS Desktop amd64'))
    state = CharField(max_length=10, choices=STATES, default='NEW')
    disks = ManyToManyField(Disk, verbose_name=_('disks'),
                            related_name='template_set',
                            help_text=_('Disks which are to be mounted.'))

    class Meta:
        app_label = 'vm'
        db_table = 'vm_instancetemplate'
        ordering = ['name', ]
        permissions = (
            ('create_template', _('Can create an instance template.')),
        )
        verbose_name = _('template')
        verbose_name_plural = _('templates')

    def __unicode__(self):
        return self.name

    def running_instances(self):
        """Returns the number of running instances of the template.
        """
        return self.instance_set.filter(state='RUNNING').count()

    @property
    def os_type(self):
        """Get the type of the template's operating system.
        """
        if self.access_method == 'rdp':
            return 'windows'
        else:
            return 'linux'


class Instance(AclBase, VirtualMachineDescModel, TimeStampedModel):

    """Virtual machine instance.

    Every instance has:
      * a name and a description
      * an optional parent template
      * associated share
      * a generated password for login authentication
      * time of deletion and time of suspension
      * lease times (suspension & deletion)
      * last boot timestamp
      * host node
      * current state (libvirt domain state)
      * time of creation and last modification
      * base resource configuration values
      * owner and privilege information
    """
    STATES = [('NOSTATE', _('nostate')),
              ('RUNNING', _('running')),
              ('BLOCKED', _('blocked')),
              ('PAUSED', _('paused')),
              ('SHUTDOWN', _('shutdown')),
              ('SHUTOFF', _('shutoff')),
              ('CRASHED', _('crashed')),
              ('PMSUSPENDED', _('pmsuspended'))]  # libvirt domain states
    ACL_LEVELS = (
        ('user', _('user')),          # see all details
        ('operator', _('operator')),  # console, networking, change state
        ('owner', _('owner')),        # superuser, can delete, delegate perms
    )
    name = CharField(blank=True, max_length=100, verbose_name=_('name'),
                     help_text=_("Human readable name of instance."))
    description = TextField(blank=True, verbose_name=_('description'))
    template = ForeignKey(InstanceTemplate, blank=True, null=True,
                          related_name='instance_set',
                          help_text=_("Template the instance derives from."),
                          verbose_name=_('template'))
    pw = CharField(help_text=_("Original password of the instance."),
                   max_length=20, verbose_name=_('password'))
    time_of_suspend = DateTimeField(blank=True, default=None, null=True,
                                    verbose_name=_('time of suspend'),
                                    help_text=_("Proposed time of automatic "
                                                "suspension."))
    time_of_delete = DateTimeField(blank=True, default=None, null=True,
                                   verbose_name=_('time of delete'),
                                   help_text=_("Proposed time of automatic "
                                               "deletion."))
    active_since = DateTimeField(blank=True, null=True,
                                 help_text=_("Time stamp of successful "
                                             "boot report."),
                                 verbose_name=_('active since'))
    node = ForeignKey(Node, blank=True, null=True,
                      related_name='instance_set',
                      help_text=_("Current hypervisor of this instance."),
                      verbose_name=_('host node'))
    state = CharField(choices=STATES, default='NOSTATE', max_length=20)
    disks = ManyToManyField(Disk, related_name='instance_set',
                            help_text=_("Set of mounted disks."),
                            verbose_name=_('disks'))
    vnc_port = IntegerField(blank=True, default=None, null=True,
                            help_text=_("TCP port where VNC console listens."),
                            unique=True, verbose_name=_('vnc_port'))
    owner = ForeignKey(User)
    destroyed = DateTimeField(blank=True, null=True,
                              help_text=_("The virtual machine's time of "
                                          "destruction."))
    objects = Manager()
    active = InstanceActiveManager()

    class Meta:
        app_label = 'vm'
        db_table = 'vm_instance'
        ordering = ['pk', ]
        permissions = (
            ('access_console', _('Can access the graphical console of a VM.')),
            ('change_resources', _('Can change resources of a running VM.')),
            ('set_resources', _('Can change resources of a new VM.')),
            ('config_ports', _('Can configure port forwards.')),
        )
        verbose_name = _('instance')
        verbose_name_plural = _('instances')

    def __unicode__(self):
        parts = [self.name, "(" + str(self.id) + ")"]
        return " ".join([s for s in parts if s != ""])

    def clean(self, *args, **kwargs):
        if self.time_of_delete is None:
            self.renew(which='delete')
        super(Instance, self).clean(*args, **kwargs)

    @classmethod
    def create_from_template(cls, template, owner, disks=None, networks=None,
                             req_traits=None, tags=None, **kwargs):
        """Create a new instance based on an InstanceTemplate.

        Can also specify parameters as keyword arguments which should override
        template settings.
        """
        insts = cls.mass_create_from_template(template, owner, disks=disks,
                                              networks=networks, tags=tags,
                                              req_traits=req_traits, **kwargs)
        return insts[0]

    @classmethod
    def mass_create_from_template(cls, template, owner, amount=1, disks=None,
                                  networks=None, req_traits=None, tags=None,
                                  **kwargs):
        """Mass-create new instances based on an InstanceTemplate.

        Can also specify parameters as keyword arguments which should override
        template settings.
        """
        disks = template.disks.all() if disks is None else disks

        for disk in disks:
            if not disk.has_level(owner, 'user'):
                raise PermissionDenied()
            elif (disk.type == 'qcow2-snap'
                  and not disk.has_level(owner, 'owner')):
                raise PermissionDenied()

        networks = (template.interface_set.all() if networks is None
                    else networks)

        for network in networks:
            if not network.vlan.has_level(owner, 'user'):
                raise PermissionDenied()

        req_traits = (template.req_traits.all() if req_traits is None
                      else req_traits)

        tags = template.tags.all() if tags is None else tags

        # prepare parameters
        common_fields = ['name', 'description', 'num_cores', 'ram_size',
                         'max_ram_size', 'arch', 'priority', 'boot_menu',
                         'raw_data', 'lease', 'access_method']
        params = dict(template=template, owner=owner, pw=pwgen())
        params.update([(f, getattr(template, f)) for f in common_fields])
        params.update(kwargs)  # override defaults w/ user supplied values

        return [cls.__create_instance(params, disks, networks, req_traits,
                                      tags) for i in xrange(amount)]

    @classmethod
    def __create_instance(cls, params, disks, networks, req_traits, tags):
        # create instance and do additional setup
        inst = cls(**params)

        # save instance
        inst.clean()
        inst.save()
        inst.set_level(inst.owner, 'owner')

        # create related entities
        inst.disks.add(*[disk.get_exclusive() for disk in disks])

        for net in networks:
            i = Interface.create(instance=inst, vlan=net.vlan,
                                 owner=inst.owner, managed=net.managed)
            if i.host:
                i.host.enable_net()
                port, proto = ACCESS_PROTOCOLS[i.instance.access_method][1:3]
                # TODO fix this port fw
                i.host.add_port(proto, private=port)

        inst.req_traits.add(*req_traits)
        inst.tags.add(*tags)

        return inst

    @permalink
    def get_absolute_url(self):
        return ('dashboard.views.detail', None, {'pk': self.id})

    @property
    def vm_name(self):
        """Name of the VM instance.

        This is a unique identifier as opposed to the 'name' attribute, which
        is just for display.
        """
        return 'cloud-' + str(self.id)

    @property
    def mem_dump(self):
        """Return the path and datastore for the memory dump.

        It is always on the first hard drive storage named cloud-<id>.dump
        """
        datastore = self.disks.all()[0].datastore
        path = datastore.path + '/' + self.vm_name + '.dump'
        return {'datastore': datastore, 'path': path}

    @property
    def primary_host(self):
        interfaces = self.interface_set.select_related('host')
        hosts = [i.host for i in interfaces if i.host]
        if not hosts:
            return None
        hs = [h for h in hosts if h.ipv6]
        if hs:
            return hs[0]
        hs = [h for h in hosts if not h.shared_ip]
        if hs:
            return hs[0]
        return hosts[0]

    @property
    def ipv4(self):
        """Primary IPv4 address of the instance.
        """
        return self.primary_host.ipv4 if self.primary_host else None

    @property
    def ipv6(self):
        """Primary IPv6 address of the instance.
        """
        return self.primary_host.ipv6 if self.primary_host else None

    @property
    def mac(self):
        """Primary MAC address of the instance.
        """
        return self.primary_host.mac if self.primary_host else None

    @property
    def uptime(self):
        """Uptime of the instance.
        """
        if self.active_since:
            return timezone.now() - self.active_since
        else:
            return timedelta()  # zero

    def get_age(self):
        """Deprecated. Use uptime instead.

        Get age of VM in seconds.
        """
        return self.uptime.seconds

    @property
    def waiting(self):
        """Indicates whether the instance's waiting for an operation to finish.
        """
        return self.activity_log.filter(finished__isnull=True).exists()

    def get_connect_port(self, use_ipv6=False):
        """Get public port number for default access method.
        """
        port, proto = ACCESS_PROTOCOLS[self.access_method][1:3]
        if self.primary_host:
            endpoints = self.primary_host.get_public_endpoints(port, proto)
            endpoint = endpoints['ipv6'] if use_ipv6 else endpoints['ipv4']
            return endpoint[1] if endpoint else None
        else:
            return None

    def get_connect_host(self, use_ipv6=False):
        """Get public hostname.
        """
        if not self.interface_set.exclude(host=None):
            return _('None')
        proto = 'ipv6' if use_ipv6 else 'ipv4'
        return self.interface_set.exclude(host=None)[0].host.get_hostname(
            proto=proto)

    def get_connect_command(self, use_ipv6=False):
        try:
            port = self.get_connect_port(use_ipv6=use_ipv6)
            host = self.get_connect_host(use_ipv6=use_ipv6)
            proto = self.access_method
            print proto
            if proto == 'rdp':
                return 'rdesktop %(host)s:%(port)d -u cloud -p %(pw)s' % {
                    'port': port, 'proto': proto, 'pw': self.pw,
                    'host': host}
            elif proto == 'ssh':
                return ('sshpass -p %(pw)s ssh -o StrictHostKeyChecking=n '
                        'cloud@%(host)s -p %(port)d') % {
                    'port': port, 'proto': proto, 'pw': self.pw,
                    'host': host}
        except:
            return

    def get_connect_uri(self, use_ipv6=False):
        """Get access parameters in URI format.
        """
        try:
            port = self.get_connect_port(use_ipv6=use_ipv6)
            host = self.get_connect_host(use_ipv6=use_ipv6)
            proto = self.access_method
            if proto == 'ssh':
                proto = 'sshterm'
            return ('%(proto)s:cloud:%(pw)s:%(host)s:%(port)d' %
                    {'port': port, 'proto': proto, 'pw': self.pw,
                     'host': host})
        except:
            return

    def get_vm_desc(self):
        return {
            'name': self.vm_name,
            'vcpu': self.num_cores,
            'memory': int(self.ram_size) * 1024,  # convert from MiB to KiB
            'memory_max': int(self.max_ram_size) * 1024,  # convert MiB to KiB
            'cpu_share': self.priority,
            'arch': self.arch,
            'boot_menu': self.boot_menu,
            'network_list': [n.get_vmnetwork_desc()
                             for n in self.interface_set.all()],
            'disk_list': [d.get_vmdisk_desc() for d in self.disks.all()],
            'graphics': {
                'type': 'vnc',
                'listen': '0.0.0.0',
                'passwd': '',
                'port': self.vnc_port
            },
            'boot_token': signing.dumps(self.id, salt='activate'),
            'raw_data': "" if not self.raw_data else self.raw_data
        }

    def get_remote_queue_name(self, queue_id):
        """Get the remote worker queue name of this instance with the specified
           queue ID.
        """
        return self.node.get_remote_queue_name(queue_id) if self.node else None

    def renew(self, which='both'):
        """Renew virtual machine instance leases.
        """
        if which not in ['suspend', 'delete', 'both']:
            raise ValueError('No such expiration type.')
        if which in ['suspend', 'both']:
            self.time_of_suspend = timezone.now() + self.lease.suspend_interval
        if which in ['delete', 'both']:
            self.time_of_delete = timezone.now() + self.lease.delete_interval
        self.save()

    def change_password(self, user=None):
        """Generate new password for the vm

        :param self: The virtual machine.

        :param user: The user who's issuing the command.
        """

        self.pw = pwgen()
        with instance_activity(code_suffix='change_password', instance=self,
                               user=user):
            queue = "%s.agent" % self.node.host.hostname
            agent_tasks.change_password.apply_async(queue=queue,
                                                    args=(self.vm_name,
                                                          self.pw))
        self.save()

    def __schedule_vm(self, act):
        """Schedule the virtual machine.

        :param self: The virtual machine.

        :param act: Parent activity.
        """
        # Find unused port for VNC
        if self.vnc_port is None:
            self.vnc_port = find_unused_vnc_port()

        # Schedule
        if self.node is None:
            self.node = scheduler.select_node(self, Node.objects.all())

        self.save()

    def __deploy_vm(self, act):
        """Deploy the virtual machine.

        :param self: The virtual machine.

        :param act: Parent activity.
        """
        queue_name = self.get_remote_queue_name('vm')

        # Deploy VM on remote machine
        with act.sub_activity('deploying_vm'):
            vm_tasks.deploy.apply_async(args=[self.get_vm_desc()],
                                        queue=queue_name).get()

        # Estabilish network connection (vmdriver)
        with act.sub_activity('deploying_net'):
            for net in self.interface_set.all():
                net.deploy()

        # Resume vm
        with act.sub_activity('booting'):
            vm_tasks.resume.apply_async(args=[self.vm_name],
                                        queue=queue_name).get()

        self.renew('suspend')

    def deploy(self, user=None, task_uuid=None):
        """Deploy new virtual machine with network

        :param self: The virtual machine to deploy.
        :type self: vm.models.Instance

        :param user: The user who's issuing the command.
        :type user: django.contrib.auth.models.User

        :param task_uuid: The task's UUID, if the command is being executed
                          asynchronously.
        :type task_uuid: str
        """
        with instance_activity(code_suffix='deploy', instance=self,
                               task_uuid=task_uuid, user=user) as act:

            # Clear destroyed flag
            self.destroyed = None

            self.__schedule_vm(act)

            # Deploy virtual images
            with act.sub_activity('deploying_disks'):
                devnums = list(string.ascii_lowercase)  # a-z
                for disk in self.disks.all():
                    # assign device numbers
                    if disk.dev_num in devnums:
                        devnums.remove(disk.dev_num)
                    else:
                        disk.dev_num = devnums.pop(0)
                        disk.save()
                    # deploy disk
                    disk.deploy()

            self.__deploy_vm(act)

    def deploy_async(self, user=None):
        """Execute deploy asynchronously.
        """
        logger.debug('Calling async local_tasks.deploy(%s, %s)',
                     unicode(self), unicode(user))
        return local_tasks.deploy.apply_async(args=[self, user],
                                              queue="localhost.man")

    def __destroy_vm(self, act):
        """Destroy the virtual machine and its associated networks.

        :param self: The virtual machine.

        :param act: Parent activity.
        """
        # Destroy networks
        with act.sub_activity('destroying_net'):
            for net in self.interface_set.all():
                net.destroy()

        # Destroy virtual machine
        with act.sub_activity('destroying_vm'):
            queue_name = self.get_remote_queue_name('vm')
            vm_tasks.destroy.apply_async(args=[self.vm_name],
                                         queue=queue_name).get()

    def __cleanup_after_destroy_vm(self, act):
        """Clean up the virtual machine's data after destroy.

        :param self: The virtual machine.

        :param act: Parent activity.
        """
        # Delete mem. dump if exists
        queue_name = self.mem_dump['datastore'].get_remote_queue_name(
            'storage')
        try:
            from storage.tasks.remote_tasks import delete
            delete.apply_async(args=[self.mem_dump['path']],
                               queue=queue_name).get()
        except:
            pass

        # Clear node and VNC port association
        self.node = None
        self.vnc_port = None

    def redeploy(self, user=None, task_uuid=None):
        """Redeploy virtual machine with network

        :param self: The virtual machine to redeploy.

        :param user: The user who's issuing the command.
        :type user: django.contrib.auth.models.User

        :param task_uuid: The task's UUID, if the command is being executed
                          asynchronously.
        :type task_uuid: str
        """
        with instance_activity(code_suffix='redeploy', instance=self,
                               task_uuid=task_uuid, user=user) as act:
            # Destroy VM
            if self.node:
                self.__destroy_vm(act)

            self.__cleanup_after_destroy_vm(act)

            # Deploy VM
            self.__schedule_vm(act)

            self.__deploy_vm(act)

    def redeploy_async(self, user=None):
        """Execute redeploy asynchronously.
        """
        return local_tasks.redeploy.apply_async(args=[self, user],
                                                queue="localhost.man")

    def destroy(self, user=None, task_uuid=None):
        """Remove virtual machine and its networks.

        :param self: The virtual machine to destroy.
        :type self: vm.models.Instance

        :param user: The user who's issuing the command.
        :type user: django.contrib.auth.models.User

        :param task_uuid: The task's UUID, if the command is being executed
                          asynchronously.
        :type task_uuid: str
        """
        if self.destroyed:
            return  # already destroyed, nothing to do here

        with instance_activity(code_suffix='destroy', instance=self,
                               task_uuid=task_uuid, user=user) as act:

            if self.node:
                self.__destroy_vm(act)

            # Destroy disks
            with act.sub_activity('destroying_disks'):
                for disk in self.disks.all():
                    disk.destroy()

            self.__cleanup_after_destroy_vm(act)

            self.destroyed = timezone.now()
            self.save()

    def destroy_async(self, user=None):
        """Execute destroy asynchronously.
        """
        return local_tasks.destroy.apply_async(args=[self, user],
                                               queue="localhost.man")

    def sleep(self, user=None, task_uuid=None):
        """Suspend virtual machine with memory dump.
        """
        with instance_activity(code_suffix='sleep', instance=self,
                               task_uuid=task_uuid, user=user):

            queue_name = self.get_remote_queue_name('vm')
            vm_tasks.sleep.apply_async(args=[self.vm_name,
                                             self.mem_dump['path']],
                                       queue=queue_name).get()

    def sleep_async(self, user=None):
        """Execute sleep asynchronously.
        """
        return local_tasks.sleep.apply_async(args=[self, user],
                                             queue="localhost.man")

    def wake_up(self, user=None, task_uuid=None):
        with instance_activity(code_suffix='wake_up', instance=self,
                               task_uuid=task_uuid, user=user):

            queue_name = self.get_remote_queue_name('vm')
            vm_tasks.resume.apply_async(args=[self.vm_name, self.dump_mem],
                                        queue=queue_name).get()

    def wake_up_async(self, user=None):
        """Execute wake_up asynchronously.
        """
        return local_tasks.wake_up.apply_async(args=[self, user],
                                               queue="localhost.man")

    def shutdown(self, user=None, task_uuid=None):
        """Shutdown virtual machine with ACPI signal.
        """
        with instance_activity(code_suffix='shutdown', instance=self,
                               task_uuid=task_uuid, user=user):

            queue_name = self.get_remote_queue_name('vm')
            vm_tasks.shutdown.apply_async(args=[self.vm_name],
                                          queue=queue_name).get()

    def shutdown_async(self, user=None):
        """Execute shutdown asynchronously.
        """
        return local_tasks.shutdown.apply_async(args=[self, user],
                                                queue="localhost.man")

    def reset(self, user=None, task_uuid=None):
        """Reset virtual machine (reset button)
        """
        with instance_activity(code_suffix='reset', instance=self,
                               task_uuid=task_uuid, user=user):

            queue_name = self.get_remote_queue_name('vm')
            vm_tasks.restart.apply_async(args=[self.vm_name],
                                         queue=queue_name).get()

    def reset_async(self, user=None):
        """Execute reset asynchronously.
        """
        return local_tasks.restart.apply_async(args=[self, user],
                                               queue="localhost.man")

    def reboot(self, user=None, task_uuid=None):
        """Reboot virtual machine with Ctrl+Alt+Del signal.
        """
        with instance_activity(code_suffix='reboot', instance=self,
                               task_uuid=task_uuid, user=user):

            queue_name = self.get_remote_queue_name('vm')
            vm_tasks.reboot.apply_async(args=[self.vm_name],
                                        queue=queue_name).get()

    def reboot_async(self, user=None):
        """Execute reboot asynchronously. """
        return local_tasks.reboot.apply_async(args=[self, user],
                                              queue="localhost.man")

    def migrate_async(self, to_node, user=None):
        """Execute migrate asynchronously. """
        return local_tasks.migrate.apply_async(args=[self, to_node, user],
                                               queue="localhost.man")

    def migrate(self, to_node, user=None, task_uuid=None):
        """Live migrate running vm to another node. """
        with instance_activity(code_suffix='migrate', instance=self,
                               task_uuid=task_uuid, user=user) as act:
            # Destroy networks
            with act.sub_activity('destroying_net'):
                for net in self.interface_set.all():
                    net.destroy()

            with act.sub_activity('migrate_vm'):
                queue_name = self.get_remote_queue_name('vm')
                vm_tasks.migrate.apply_async(args=[self.vm_name,
                                             to_node.host.hostname],
                                             queue=queue_name).get()
            # Refresh node information
            self.node = to_node
            self.save()
            # Estabilish network connection (vmdriver)
            with act.sub_activity('deploying_net'):
                for net in self.interface_set.all():
                    net.deploy()

    def save_as_template(self, name, **kwargs):
        # prepare parameters
        kwargs.setdefault('name', name)
        kwargs.setdefault('description', self.description)
        kwargs.setdefault('parent', self.template)
        kwargs.setdefault('num_cores', self.num_cores)
        kwargs.setdefault('ram_size', self.ram_size)
        kwargs.setdefault('max_ram_size', self.max_ram_size)
        kwargs.setdefault('arch', self.arch)
        kwargs.setdefault('priority', self.priority)
        kwargs.setdefault('boot_menu', self.boot_menu)
        kwargs.setdefault('raw_data', self.raw_data)
        kwargs.setdefault('lease', self.lease)
        kwargs.setdefault('access_method', self.access_method)
        kwargs.setdefault('system', self.template.system
                          if self.template else None)
        # create template and do additional setup
        tmpl = InstanceTemplate(**kwargs)
        # save template
        tmpl.save()
        # create related entities
        for disk in self.disks.all():
            try:
                d = disk.save_as()
            except Disk.WrongDiskTypeError:
                d = disk

            tmpl.disks.add(d)

        for i in self.interface_set.all():
            i.save_as_template(tmpl)

        return tmpl

    def state_changed(self, new_state):
        logger.debug('Instance %s state changed '
                     '(db: %s, new: %s)',
                     self, self.state, new_state)
        try:
            pre_state_changed.send(sender=self, new_state=new_state)
        except Exception as e:
            logger.info('Instance %s state change ignored: %s',
                        unicode(self), unicode(e))
        else:
            self.state = new_state
            self.save()
            post_state_changed.send(sender=self, new_state=new_state)