Synnefo

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from django.conf import settings

from django.db import transaction

from datetime import datetime

from synnefo.db.models import (Backend, VirtualMachine, Network,

                               FloatingIP,

                               BackendNetwork, BACKEND_STATUSES,

                               pooled_rapi_client, VirtualMachineDiagnostic,

                               Flavor)

from synnefo.logic import utils

from synnefo import quotas

from synnefo.api.util import release_resource

from synnefo.util.mac2eui64 import mac2eui64

from synnefo.logic.rapi import GanetiApiError

from logging import getLogger

log = getLogger(__name__)

_firewall_tags = {

    'ENABLED': settings.GANETI_FIREWALL_ENABLED_TAG,

    'DISABLED': settings.GANETI_FIREWALL_DISABLED_TAG,

    'PROTECTED': settings.GANETI_FIREWALL_PROTECTED_TAG}

_reverse_tags = dict((v.split(':')[3], k) for k, v in _firewall_tags.items())

def handle_vm_quotas(vm, job_id, job_opcode, job_status, job_fields):

    """Handle quotas for updated VirtualMachine.

    Update quotas for the updated VirtualMachine based on the job that run on

    the Ganeti backend. If a commission has been already issued for this job,

    then this commission is just accepted or rejected based on the job status.

    Otherwise, a new commission for the given change is issued, that is also in

    force and auto-accept mode. In this case, previous commissions are

    rejected, since they reflect a previous state of the VM.

    """

    if job_status not in ["success", "error", "canceled"]:

        return vm

    # Check successful completion of a job will trigger any quotable change in

    # the VM state.

    action = utils.get_action_from_opcode(job_opcode, job_fields)

    if action == "BUILD":

        # Quotas for new VMs are automatically accepted by the API

        return vm

    commission_info = quotas.get_commission_info(vm, action=action,

                                                 action_fields=job_fields)

    if vm.task_job_id == job_id and vm.serial is not None:

        # Commission for this change has already been issued. So just

        # accept/reject it. Special case is OP_INSTANCE_CREATE, which even

        # if fails, must be accepted, as the user must manually remove the

        # failed server

        serial = vm.serial

        if job_status == "success":

            quotas.accept_serial(serial)

        elif job_status in ["error", "canceled"]:

            log.debug("Job %s failed. Rejecting related serial %s", job_id,

                      serial)

            quotas.reject_serial(serial)

        vm.serial = None

    elif job_status == "success" and commission_info is not None:

        log.debug("Expected job was %s. Processing job %s. Commission for"

                  " this job: %s", vm.task_job_id, job_id, commission_info)

        # Commission for this change has not been issued, or the issued

        # commission was unaware of the current change. Reject all previous

        # commissions and create a new one in forced mode!

        commission_name = ("client: dispatcher, resource: %s, ganeti_job: %s"

                           % (vm, job_id))

        quotas.handle_resource_commission(vm, action,

                                          commission_info=commission_info,

                                          commission_name=commission_name,

                                          force=True,

                                          auto_accept=True)

        log.debug("Issued new commission: %s", vm.serial)

    return vm

@transaction.commit_on_success

def process_op_status(vm, etime, jobid, opcode, status, logmsg, nics=None,

                      beparams=None):

    """Process a job progress notification from the backend

    Process an incoming message from the backend (currently Ganeti).

    Job notifications with a terminating status (sucess, error, or canceled),

    also update the operating state of the VM.

    """

    # See #1492, #1031, #1111 why this line has been removed

    #if (opcode not in [x[0] for x in VirtualMachine.BACKEND_OPCODES] or

    if status not in [x[0] for x in BACKEND_STATUSES]:

        raise VirtualMachine.InvalidBackendMsgError(opcode, status)

    vm.backendjobid = jobid

    vm.backendjobstatus = status

    vm.backendopcode = opcode

    vm.backendlogmsg = logmsg

    if status in ["queued", "waiting", "running"]:

        vm.save()

        return

    state_for_success = VirtualMachine.OPER_STATE_FROM_OPCODE.get(opcode)

    # Notifications of success change the operating state

    if status == "success":

        if state_for_success is not None:

            vm.operstate = state_for_success

        if beparams:

            # Change the flavor of the VM

            _process_resize(vm, beparams)

        # Update backendtime only for jobs that have been successfully

        # completed, since only these jobs update the state of the VM. Else a

        # "race condition" may occur when a successful job (e.g.

        # OP_INSTANCE_REMOVE) completes before an error job and messages arrive

        # in reversed order.

        vm.backendtime = etime

    if status in ["success", "error", "canceled"] and nics is not None:

        # Update the NICs of the VM

        _process_net_status(vm, etime, nics)

    # Special case: if OP_INSTANCE_CREATE fails --> ERROR

    if opcode == 'OP_INSTANCE_CREATE' and status in ('canceled', 'error'):

        vm.operstate = 'ERROR'

        vm.backendtime = etime

    elif opcode == 'OP_INSTANCE_REMOVE':

        # Special case: OP_INSTANCE_REMOVE fails for machines in ERROR,

        # when no instance exists at the Ganeti backend.

        # See ticket #799 for all the details.

        if status == 'success' or (status == 'error' and

                                   not vm_exists_in_backend(vm)):

            # VM has been deleted. Release the instance IPs

            release_instance_ips(vm, [])

            # And delete the releated NICs (must be performed after release!)

            vm.nics.all().delete()

            vm.deleted = True

            vm.operstate = state_for_success

            vm.backendtime = etime

            status = "success"

    if status in ["success", "error", "canceled"]:

        # Job is finalized: Handle quotas/commissioning

        job_fields = {"nics": nics, "beparams": beparams}

        vm = handle_vm_quotas(vm, job_id=jobid, job_opcode=opcode,

                              job_status=status, job_fields=job_fields)

        # and clear task fields

        if vm.task_job_id == jobid:

            vm.task = None

            vm.task_job_id = None

    vm.save()

def _process_resize(vm, beparams):

    """Change flavor of a VirtualMachine based on new beparams."""

    old_flavor = vm.flavor

    vcpus = beparams.get("vcpus", old_flavor.cpu)

    ram = beparams.get("maxmem", old_flavor.ram)

    if vcpus == old_flavor.cpu and ram == old_flavor.ram:

        return

    try:

        new_flavor = Flavor.objects.get(cpu=vcpus, ram=ram,

                                        disk=old_flavor.disk,

                                        disk_template=old_flavor.disk_template)

    except Flavor.DoesNotExist:

        raise Exception("Can not find flavor for VM")

    vm.flavor = new_flavor

    vm.save()

@transaction.commit_on_success

def process_net_status(vm, etime, nics):

    """Wrap _process_net_status inside transaction."""

    _process_net_status(vm, etime, nics)

def _process_net_status(vm, etime, nics):

    """Process a net status notification from the backend

    Process an incoming message from the Ganeti backend,

    detailing the NIC configuration of a VM instance.

    Update the state of the VM in the DB accordingly.

    """

    ganeti_nics = process_ganeti_nics(nics)

    if not nics_changed(vm.nics.order_by('index'), ganeti_nics):

        log.debug("NICs for VM %s have not changed", vm)

        return

    # Get X-Lock on backend before getting X-Lock on network IP pools, to

    # guarantee that no deadlock will occur with Backend allocator.

    Backend.objects.select_for_update().get(id=vm.backend_id)

    # NICs have changed. Release the instance IPs

    release_instance_ips(vm, ganeti_nics)

    # And delete the releated NICs (must be performed after release!)

    vm.nics.all().delete()

    for nic in ganeti_nics:

        ipv4 = nic["ipv4"]

        net = nic['network']

        if ipv4:

            net.reserve_address(ipv4)

        nic['dirty'] = False

        vm.nics.create(**nic)

        # Dummy save the network, because UI uses changed-since for VMs

        # and Networks in order to show the VM NICs

        net.save()

    vm.backendtime = etime

    vm.save()

def process_ganeti_nics(ganeti_nics):

    """Process NIC dict from ganeti hooks."""

    new_nics = []

    for i, new_nic in enumerate(ganeti_nics):

        network = new_nic.get('network', '')

        n = str(network)

        pk = utils.id_from_network_name(n)

        net = Network.objects.get(pk=pk)

        # Get the new nic info

        mac = new_nic.get('mac')

        ipv4 = new_nic.get('ip')

        ipv6 = mac2eui64(mac, net.subnet6) if net.subnet6 is not None else None

        firewall = new_nic.get('firewall')

        firewall_profile = _reverse_tags.get(firewall)

        if not firewall_profile and net.public:

            firewall_profile = settings.DEFAULT_FIREWALL_PROFILE

        nic = {

            'index': i,

            'network': net,

            'mac': mac,

            'ipv4': ipv4,

            'ipv6': ipv6,

            'firewall_profile': firewall_profile,

            'state': 'ACTIVE'}

        new_nics.append(nic)

    return new_nics

def nics_changed(old_nics, new_nics):

    """Return True if NICs have changed in any way."""

    if len(old_nics) != len(new_nics):

        return True

    fields = ["ipv4", "ipv6", "mac", "firewall_profile", "index", "network"]

    for old_nic, new_nic in zip(old_nics, new_nics):

        for field in fields:

            if getattr(old_nic, field) != new_nic[field]:

                return True

    return False

def release_instance_ips(vm, ganeti_nics):

    old_addresses = set(vm.nics.values_list("network", "ipv4"))

    new_addresses = set(map(lambda nic: (nic["network"].id, nic["ipv4"]),

                            ganeti_nics))

    to_release = old_addresses - new_addresses

    for (network_id, ipv4) in to_release:

        if ipv4:

            # Get X-Lock before searching floating IP, to exclusively search

            # and release floating IP. Otherwise you may release a floating IP

            # that has been just reserved.

            net = Network.objects.select_for_update().get(id=network_id)

            if net.floating_ip_pool:

                try:

                    floating_ip = net.floating_ips.select_for_update()\

                                                  .get(ipv4=ipv4, machine=vm,

                                                       deleted=False)

                    floating_ip.machine = None

                    floating_ip.save()

                except FloatingIP.DoesNotExist:

                    net.release_address(ipv4)

            else:

                net.release_address(ipv4)

@transaction.commit_on_success

def process_network_status(back_network, etime, jobid, opcode, status, logmsg):

    if status not in [x[0] for x in BACKEND_STATUSES]:

        raise Network.InvalidBackendMsgError(opcode, status)

    back_network.backendjobid = jobid

    back_network.backendjobstatus = status

    back_network.backendopcode = opcode

    back_network.backendlogmsg = logmsg

    network = back_network.network

    # Notifications of success change the operating state

    state_for_success = BackendNetwork.OPER_STATE_FROM_OPCODE.get(opcode, None)

    if status == 'success' and state_for_success is not None:

        back_network.operstate = state_for_success

    if status in ('canceled', 'error') and opcode == 'OP_NETWORK_ADD':

        back_network.operstate = 'ERROR'

        back_network.backendtime = etime

    if opcode == 'OP_NETWORK_REMOVE':

        network_is_deleted = (status == "success")

        if network_is_deleted or (status == "error" and not

                                  network_exists_in_backend(back_network)):

            back_network.operstate = state_for_success

            back_network.deleted = True

            back_network.backendtime = etime

    if status == 'success':

        back_network.backendtime = etime

    back_network.save()

    # Also you must update the state of the Network!!

    update_network_state(network)

def update_network_state(network):

    """Update the state of a Network based on BackendNetwork states.

    Update the state of a Network based on the operstate of the networks in the

    backends that network exists.

    The state of the network is:

    * ACTIVE: If it is 'ACTIVE' in at least one backend.

    * DELETED: If it is is 'DELETED' in all backends that have been created.

    This function also releases the resources (MAC prefix or Bridge) and the

    quotas for the network.

    """

    if network.deleted:

        # Network has already been deleted. Just assert that state is also

        # DELETED

        if not network.state == "DELETED":

            network.state = "DELETED"

            network.save()

        return

    backend_states = [s.operstate for s in network.backend_networks.all()]

    if not backend_states and network.action != "DESTROY":

        if network.state != "ACTIVE":

            network.state = "ACTIVE"

            network.save()

            return

    # Network is deleted when all BackendNetworks go to "DELETED" operstate

    deleted = reduce(lambda x, y: x == y and "DELETED", backend_states,

                     "DELETED")

    # Release the resources on the deletion of the Network

    if deleted:

        log.info("Network %r deleted. Releasing link %r mac_prefix %r",

                 network.id, network.mac_prefix, network.link)

        network.deleted = True

        network.state = "DELETED"

        if network.mac_prefix:

            if network.FLAVORS[network.flavor]["mac_prefix"] == "pool":

                release_resource(res_type="mac_prefix",

                                 value=network.mac_prefix)

        if network.link:

            if network.FLAVORS[network.flavor]["link"] == "pool":

                release_resource(res_type="bridge", value=network.link)

        # Issue commission

        if network.userid:

            quotas.issue_and_accept_commission(network, delete=True)

            # the above has already saved the object and committed;

            # a second save would override others' changes, since the

            # object is now unlocked

            return

        elif not network.public:

            log.warning("Network %s does not have an owner!", network.id)

    network.save()

@transaction.commit_on_success

def process_network_modify(back_network, etime, jobid, opcode, status,

                           add_reserved_ips):

    assert (opcode == "OP_NETWORK_SET_PARAMS")

    if status not in [x[0] for x in BACKEND_STATUSES]:

        raise Network.InvalidBackendMsgError(opcode, status)

    back_network.backendjobid = jobid

    back_network.backendjobstatus = status

    back_network.opcode = opcode

    if add_reserved_ips:

        net = back_network.network

        pool = net.get_pool()

        if add_reserved_ips:

            for ip in add_reserved_ips:

                pool.reserve(ip, external=True)

        pool.save()

    if status == 'success':

        back_network.backendtime = etime

    back_network.save()

@transaction.commit_on_success

def process_create_progress(vm, etime, progress):

    percentage = int(progress)

    # The percentage may exceed 100%, due to the way

    # snf-image:copy-progress tracks bytes read by image handling processes

    percentage = 100 if percentage > 100 else percentage

    if percentage < 0:

        raise ValueError("Percentage cannot be negative")

    # FIXME: log a warning here, see #1033

#   if last_update > percentage:

#       raise ValueError("Build percentage should increase monotonically " \

#                        "(old = %d, new = %d)" % (last_update, percentage))

    # This assumes that no message of type 'ganeti-create-progress' is going to

    # arrive once OP_INSTANCE_CREATE has succeeded for a Ganeti instance and

    # the instance is STARTED.  What if the two messages are processed by two

    # separate dispatcher threads, and the 'ganeti-op-status' message for

    # successful creation gets processed before the 'ganeti-create-progress'

    # message? [vkoukis]

    #

    #if not vm.operstate == 'BUILD':

    #    raise VirtualMachine.IllegalState("VM is not in building state")

    vm.buildpercentage = percentage

    vm.backendtime = etime

    vm.save()

@transaction.commit_on_success

def create_instance_diagnostic(vm, message, source, level="DEBUG", etime=None,

                               details=None):

    """

    Create virtual machine instance diagnostic entry.

    :param vm: VirtualMachine instance to create diagnostic for.

    :param message: Diagnostic message.

    :param source: Diagnostic source identifier (e.g. image-helper).

    :param level: Diagnostic level (`DEBUG`, `INFO`, `WARNING`, `ERROR`).

    :param etime: The time the message occured (if available).

    :param details: Additional details or debug information.

    """

    VirtualMachineDiagnostic.objects.create_for_vm(vm, level, source=source,

                                                   source_date=etime,

                                                   message=message,

                                                   details=details)

def create_instance(vm, nics, flavor, image):

    """`image` is a dictionary which should contain the keys:

            'backend_id', 'format' and 'metadata'

        metadata value should be a dictionary.

    """

    # Handle arguments to CreateInstance() as a dictionary,

    # initialize it based on a deployment-specific value.

    # This enables the administrator to override deployment-specific

    # arguments, such as the disk template to use, name of os provider

    # and hypervisor-specific parameters at will (see Synnefo #785, #835).

    #

    kw = vm.backend.get_create_params()

    kw['mode'] = 'create'

    kw['name'] = vm.backend_vm_id

    # Defined in settings.GANETI_CREATEINSTANCE_KWARGS

    kw['disk_template'] = flavor.disk_template

    kw['disks'] = [{"size": flavor.disk * 1024}]

    provider = flavor.disk_provider

    if provider:

        kw['disks'][0]['provider'] = provider

        kw['disks'][0]['origin'] = flavor.disk_origin

    kw['nics'] = [{"network": nic.network.backend_id, "ip": nic.ipv4}

                  for nic in nics]

    backend = vm.backend

    depend_jobs = []

    for nic in nics:

        network = Network.objects.select_for_update().get(id=nic.network.id)

        bnet, created = BackendNetwork.objects.get_or_create(backend=backend,

                                                             network=network)

        if bnet.operstate != "ACTIVE":

            if network.public:

                msg = "Can not connect instance to network %s. Network is not"\

                      " ACTIVE in backend %s." % (network, backend)

                raise Exception(msg)

            else:

                jobs = create_network(network, backend, connect=True)

                if isinstance(jobs, list):

                    depend_jobs.extend(jobs)

                else:

                    depend_jobs.append(jobs)

    kw["depends"] = [[job, ["success", "error", "canceled"]]

                     for job in depend_jobs]

    if vm.backend.use_hotplug():

        kw['hotplug'] = True

    # Defined in settings.GANETI_CREATEINSTANCE_KWARGS

    # kw['os'] = settings.GANETI_OS_PROVIDER

    kw['ip_check'] = False

    kw['name_check'] = False

    # Do not specific a node explicitly, have

    # Ganeti use an iallocator instead

    #kw['pnode'] = rapi.GetNodes()[0]

    kw['dry_run'] = settings.TEST

    kw['beparams'] = {

        'auto_balance': True,

        'vcpus': flavor.cpu,

        'memory': flavor.ram}

    kw['osparams'] = {

        'config_url': vm.config_url,

        # Store image id and format to Ganeti

        'img_id': image['backend_id'],

        'img_format': image['format']}

    # Use opportunistic locking

    kw['opportunistic_locking'] = True

    # Defined in settings.GANETI_CREATEINSTANCE_KWARGS

    # kw['hvparams'] = dict(serial_console=False)

    log.debug("Creating instance %s", utils.hide_pass(kw))

    with pooled_rapi_client(vm) as client:

        return client.CreateInstance(**kw)

def delete_instance(vm):

    with pooled_rapi_client(vm) as client:

        return client.DeleteInstance(vm.backend_vm_id, dry_run=settings.TEST)

def reboot_instance(vm, reboot_type):

    assert reboot_type in ('soft', 'hard')

    kwargs = {"instance": vm.backend_vm_id,

              "reboot_type": "hard"}

    # XXX: Currently shutdown_timeout parameter is not supported from the

    # Ganeti RAPI. Until supported, we will fallback for both reboot types

    # to the default shutdown timeout of Ganeti (120s). Note that reboot

    # type of Ganeti job must be always hard. The 'soft' and 'hard' type

    # of OS API is different from the one in Ganeti, and maps to

    # 'shutdown_timeout'.

    #if reboot_type == "hard":

    #    kwargs["shutdown_timeout"] = 0

    if settings.TEST:

        kwargs["dry_run"] = True

    with pooled_rapi_client(vm) as client:

        return client.RebootInstance(**kwargs)

def startup_instance(vm):

    with pooled_rapi_client(vm) as client:

        return client.StartupInstance(vm.backend_vm_id, dry_run=settings.TEST)

def shutdown_instance(vm):

    with pooled_rapi_client(vm) as client:

        return client.ShutdownInstance(vm.backend_vm_id, dry_run=settings.TEST)

def resize_instance(vm, vcpus, memory):

    beparams = {"vcpus": int(vcpus),

                "minmem": int(memory),

                "maxmem": int(memory)}

    with pooled_rapi_client(vm) as client:

        return client.ModifyInstance(vm.backend_vm_id, beparams=beparams)

def get_instance_console(vm):

    # RAPI GetInstanceConsole() returns endpoints to the vnc_bind_address,

    # which is a cluster-wide setting, either 0.0.0.0 or 127.0.0.1, and pretty

    # useless (see #783).

    #

    # Until this is fixed on the Ganeti side, construct a console info reply

    # directly.

    #

    # WARNING: This assumes that VNC runs on port network_port on

    #          the instance's primary node, and is probably

    #          hypervisor-specific.

    #

    log.debug("Getting console for vm %s", vm)

    console = {}

    console['kind'] = 'vnc'

    with pooled_rapi_client(vm) as client:

        i = client.GetInstance(vm.backend_vm_id)

    if vm.backend.hypervisor == "kvm" and i['hvparams']['serial_console']:

        raise Exception("hv parameter serial_console cannot be true")

    console['host'] = i['pnode']

    console['port'] = i['network_port']

    return console

def get_instance_info(vm):

    with pooled_rapi_client(vm) as client:

        return client.GetInstance(vm.backend_vm_id)

def vm_exists_in_backend(vm):

    try:

        get_instance_info(vm)

        return True

    except GanetiApiError as e:

        if e.code == 404:

            return False

        raise e

def get_network_info(backend_network):

    with pooled_rapi_client(backend_network) as client:

        return client.GetNetwork(backend_network.network.backend_id)

def network_exists_in_backend(backend_network):

    try:

        get_network_info(backend_network)

        return True

    except GanetiApiError as e:

        if e.code == 404:

            return False

def create_network(network, backend, connect=True):

    """Create a network in a Ganeti backend"""

    log.debug("Creating network %s in backend %s", network, backend)

    job_id = _create_network(network, backend)

    if connect:

        job_ids = connect_network(network, backend, depends=[job_id])

        return job_ids

    else:

        return [job_id]

def _create_network(network, backend):

    """Create a network."""

    tags = network.backend_tag

    if network.dhcp:

        tags.append('nfdhcpd')

    if network.public:

        conflicts_check = True

    else:

        conflicts_check = False

    # Use a dummy network subnet for IPv6 only networks. Currently Ganeti does

    # not support IPv6 only networks. To bypass this limitation, we create the

    # network with a dummy network subnet, and make Cyclades connect instances

    # to such networks, with address=None.

    subnet = network.subnet

    if subnet is None:

        subnet = "10.0.0.0/24"

    try:

        bn = BackendNetwork.objects.get(network=network, backend=backend)

        mac_prefix = bn.mac_prefix

    except BackendNetwork.DoesNotExist:

        raise Exception("BackendNetwork for network '%s' in backend '%s'"

                        " does not exist" % (network.id, backend.id))

    with pooled_rapi_client(backend) as client:

        return client.CreateNetwork(network_name=network.backend_id,

                                    network=subnet,

                                    network6=network.subnet6,

                                    gateway=network.gateway,

                                    gateway6=network.gateway6,

                                    mac_prefix=mac_prefix,

                                    conflicts_check=conflicts_check,

                                    tags=tags)

def connect_network(network, backend, depends=[], group=None):

    """Connect a network to nodegroups."""

    log.debug("Connecting network %s to backend %s", network, backend)

    if network.public:

        conflicts_check = True

    else:

        conflicts_check = False

    depends = [[job, ["success", "error", "canceled"]] for job in depends]

    with pooled_rapi_client(backend) as client:

        groups = [group] if group is not None else client.GetGroups()

        job_ids = []

        for group in groups:

            job_id = client.ConnectNetwork(network.backend_id, group,

                                           network.mode, network.link,

                                           conflicts_check,

                                           depends=depends)

            job_ids.append(job_id)

    return job_ids

def delete_network(network, backend, disconnect=True):

    log.debug("Deleting network %s from backend %s", network, backend)

    depends = []

    if disconnect:

        depends = disconnect_network(network, backend)

    _delete_network(network, backend, depends=depends)

def _delete_network(network, backend, depends=[]):

    depends = [[job, ["success", "error", "canceled"]] for job in depends]

    with pooled_rapi_client(backend) as client:

        return client.DeleteNetwork(network.backend_id, depends)

def disconnect_network(network, backend, group=None):

    log.debug("Disconnecting network %s to backend %s", network, backend)

    with pooled_rapi_client(backend) as client:

        groups = [group] if group is not None else client.GetGroups()

        job_ids = []

        for group in groups:

            job_id = client.DisconnectNetwork(network.backend_id, group)

            job_ids.append(job_id)

    return job_ids

def connect_to_network(vm, nic):

    network = nic.network

    backend = vm.backend

    network = Network.objects.select_for_update().get(id=network.id)

    bnet, created = BackendNetwork.objects.get_or_create(backend=backend,

                                                         network=network)

    depend_jobs = []

    if bnet.operstate != "ACTIVE":

        depend_jobs = create_network(network, backend, connect=True)

    depends = [[job, ["success", "error", "canceled"]] for job in depend_jobs]

    nic = {'ip': nic.ipv4, 'network': network.backend_id}

    log.debug("Connecting NIC %s to VM %s", nic, vm)

    kwargs = {

        "instance": vm.backend_vm_id,

        "nics": [("add", nic)],

        "depends": depends,

    }

    if vm.backend.use_hotplug():

        kwargs["hotplug"] = True

    if settings.TEST:

        kwargs["dry_run"] = True

    with pooled_rapi_client(vm) as client:

        return client.ModifyInstance(**kwargs)

def disconnect_from_network(vm, nic):

    log.debug("Removing nic of VM %s, with index %s", vm, str(nic.index))

    kwargs = {

        "instance": vm.backend_vm_id,

        "nics": [("remove", nic.index, {})],

    }

    if vm.backend.use_hotplug():

        kwargs["hotplug"] = True

    if settings.TEST:

        kwargs["dry_run"] = True

    with pooled_rapi_client(vm) as client:

        jobID = client.ModifyInstance(**kwargs)

        # If the NIC has a tag for a firewall profile it must be deleted,

        # otherwise it may affect another NIC. XXX: Deleting the tag should

        # depend on the removing the NIC, but currently RAPI client does not

        # support this, this may result in clearing the firewall profile

        # without successfully removing the NIC. This issue will be fixed with

        # use of NIC UUIDs.

        firewall_profile = nic.firewall_profile

        if firewall_profile and firewall_profile != "DISABLED":

            tag = _firewall_tags[firewall_profile] % nic.index

            client.DeleteInstanceTags(vm.backend_vm_id, [tag],

                                      dry_run=settings.TEST)

        return jobID

def set_firewall_profile(vm, profile, index=0):

    try:

        tag = _firewall_tags[profile] % index

    except KeyError:

        raise ValueError("Unsopported Firewall Profile: %s" % profile)

    log.debug("Setting tag of VM %s, NIC index %d, to %s", vm, index, profile)

    with pooled_rapi_client(vm) as client:

        # Delete previous firewall tags

        old_tags = client.GetInstanceTags(vm.backend_vm_id)

        delete_tags = [(t % index) for t in _firewall_tags.values()

                       if (t % index) in old_tags]

        if delete_tags:

            client.DeleteInstanceTags(vm.backend_vm_id, delete_tags,

                                      dry_run=settings.TEST)

        if profile != "DISABLED":

            client.AddInstanceTags(vm.backend_vm_id, [tag],

                                   dry_run=settings.TEST)

        # XXX NOP ModifyInstance call to force process_net_status to run

        # on the dispatcher

        os_name = settings.GANETI_CREATEINSTANCE_KWARGS['os']

        client.ModifyInstance(vm.backend_vm_id,

                              os_name=os_name)

    return None

def get_instances(backend, bulk=True):

    with pooled_rapi_client(backend) as c:

        return c.GetInstances(bulk=bulk)

def get_nodes(backend, bulk=True):

    with pooled_rapi_client(backend) as c:

        return c.GetNodes(bulk=bulk)

def get_jobs(backend, bulk=True):

    with pooled_rapi_client(backend) as c:

        return c.GetJobs(bulk=bulk)

def get_physical_resources(backend):

    """ Get the physical resources of a backend.

    Get the resources of a backend as reported by the backend (not the db).

    """

    nodes = get_nodes(backend, bulk=True)

    attr = ['mfree', 'mtotal', 'dfree', 'dtotal', 'pinst_cnt', 'ctotal']

    res = {}

    for a in attr:

        res[a] = 0

    for n in nodes:

        # Filter out drained, offline and not vm_capable nodes since they will

        # not take part in the vm allocation process

        can_host_vms = n['vm_capable'] and not (n['drained'] or n['offline'])

        if can_host_vms and n['cnodes']:

            for a in attr:

                res[a] += int(n[a])

    return res

def update_backend_resources(backend, resources=None):

    """ Update the state of the backend resources in db.

    """

    if not resources:

        resources = get_physical_resources(backend)

    backend.mfree = resources['mfree']

    backend.mtotal = resources['mtotal']

    backend.dfree = resources['dfree']

    backend.dtotal = resources['dtotal']

    backend.pinst_cnt = resources['pinst_cnt']

    backend.ctotal = resources['ctotal']

    backend.updated = datetime.now()

    backend.save()

def get_memory_from_instances(backend):

    """ Get the memory that is used from instances.

    Get the used memory of a backend. Note: This is different for

    the real memory used, due to kvm's memory de-duplication.

    """

    with pooled_rapi_client(backend) as client:

        instances = client.GetInstances(bulk=True)

    mem = 0

    for i in instances:

        mem += i['oper_ram']

    return mem

def get_available_disk_templates(backend):

    """Get the list of available disk templates of a Ganeti backend.

    The list contains the disk templates that are enabled in the Ganeti backend

    and also included in ipolicy-disk-templates.

    """

    with pooled_rapi_client(backend) as c:

        info = c.GetInfo()

    ipolicy_disk_templates = info["ipolicy"]["disk-templates"]

    try:

        enabled_disk_templates = info["enabled_disk_templates"]

        return [dp for dp in enabled_disk_templates

                if dp in ipolicy_disk_templates]

    except KeyError:

        # Ganeti < 2.8 does not have 'enabled_disk_templates'

        return ipolicy_disk_templates

def update_backend_disk_templates(backend):

    disk_templates = get_available_disk_templates(backend)

    backend.disk_templates = disk_templates

    backend.save()

##

## Synchronized operations for reconciliation

##

def create_network_synced(network, backend):

    result = _create_network_synced(network, backend)

    if result[0] != 'success':

        return result

    result = connect_network_synced(network, backend)

    return result

def _create_network_synced(network, backend):

    with pooled_rapi_client(backend) as client:

        job = _create_network(network, backend)

        result = wait_for_job(client, job)

    return result

def connect_network_synced(network, backend):

    with pooled_rapi_client(backend) as client:

        for group in client.GetGroups():

            job = client.ConnectNetwork(network.backend_id, group,

                                        network.mode, network.link)

            result = wait_for_job(client, job)

            if result[0] != 'success':

                return result

    return result

def wait_for_job(client, jobid):

    result = client.WaitForJobChange(jobid, ['status', 'opresult'], None, None)

    status = result['job_info'][0]

    while status not in ['success', 'error', 'cancel']:

        result = client.WaitForJobChange(jobid, ['status', 'opresult'],

                                         [result], None)

        status = result['job_info'][0]

    if status == 'success':

        return (status, None)

    else:

        error = result['job_info'][1]

        return (status, error)