Allow unshelve to a specific host (Compute API part)

This patch introduce changes to the compute API that will allow
PROJECT_ADMIN to unshelve an shelved offloaded server to a specific host.
This patch also supports the ability to unpin the availability_zone of an
instance that is bound to it.

Implements: blueprint unshelve-to-host
Change-Id: Ieb4766fdd88c469574fad823e05fe401537cdc30

nova/api/openstack/compute/shelve.py

@@ -95,14 +95,15 @@ class ShelveController(wsgi.Controller):
         context.can(shelve_policies.POLICY_ROOT % 'unshelve',
                     target={'project_id': instance.project_id})
 
-        new_az = None
+        unshelve_args = {}
+
         unshelve_dict = body['unshelve']
         support_az = api_version_request.is_supported(req, '2.77')
         if support_az and unshelve_dict:
-            new_az = unshelve_dict['availability_zone']
+            unshelve_args['new_az'] = unshelve_dict['availability_zone']
 
         try:
-            self.compute_api.unshelve(context, instance, new_az=new_az)
+            self.compute_api.unshelve(context, instance, **unshelve_args)
         except (exception.InstanceIsLocked,
                 exception.UnshelveInstanceInvalidState,
                 exception.MismatchVolumeAZException) as e:

nova/compute/api.py

@@ -380,6 +380,8 @@ def block_extended_resource_request(function):
 class API:
     """API for interacting with the compute manager."""
 
+    _sentinel = object()
+
     def __init__(self, image_api=None, network_api=None, volume_api=None):
         self.image_api = image_api or glance.API()
         self.network_api = network_api or neutron.API()
@@ -4391,31 +4393,45 @@ class API:
             context, instance=instance,
             clean_shutdown=clean_shutdown, accel_uuids=accel_uuids)
 
-    def _validate_unshelve_az(self, context, instance, availability_zone):
+    def _check_offloaded(self, context, instance):
-        """Verify the specified availability_zone during unshelve.
+        """Check if the status of an instance is SHELVE_OFFLOADED,
-
+        if not raise an exception.
-        Verifies that the server is shelved offloaded, the AZ exists and
-        if [cinder]/cross_az_attach=False, that any attached volumes are in
-        the same AZ.
-
-        :param context: nova auth RequestContext for the unshelve action
-        :param instance: Instance object for the server being unshelved
-        :param availability_zone: The user-requested availability zone in
-            which to unshelve the server.
-        :raises: UnshelveInstanceInvalidState if the server is not shelved
-            offloaded
-        :raises: InvalidRequest if the requested AZ does not exist
-        :raises: MismatchVolumeAZException if [cinder]/cross_az_attach=False
-            and any attached volumes are not in the requested AZ
         """
         if instance.vm_state != vm_states.SHELVED_OFFLOADED:
             # NOTE(brinzhang): If the server status is 'SHELVED', it still
-            # belongs to a host, the availability_zone has not changed.
+            # belongs to a host, the availability_zone should not change.
             # Unshelving a shelved offloaded server will go through the
             # scheduler to find a new host.
             raise exception.UnshelveInstanceInvalidState(
                 state=instance.vm_state, instance_uuid=instance.uuid)
 
+    def _ensure_host_in_az(self, context, host, availability_zone):
+        """Ensure the host provided belongs to the availability zone,
+        if not raise an exception.
+        """
+        if availability_zone is not None:
+            host_az = availability_zones.get_host_availability_zone(
+                context,
+                host
+            )
+            if host_az != availability_zone:
+                raise exception.UnshelveHostNotInAZ(
+                    host=host, availability_zone=availability_zone)
+
+    def _validate_unshelve_az(self, context, instance, availability_zone):
+        """Verify the specified availability_zone during unshelve.
+
+        Verifies the AZ exists and if [cinder]/cross_az_attach=False, that
+        any attached volumes are in the same AZ.
+
+        :param context: nova auth RequestContext for the unshelve action
+        :param instance: Instance object for the server being unshelved
+        :param availability_zone: The user-requested availability zone in
+            which to unshelve the server.
+        :raises: InvalidRequest if the requested AZ does not exist
+        :raises: MismatchVolumeAZException if [cinder]/cross_az_attach=False
+            and any attached volumes are not in the requested AZ
+        """
         available_zones = availability_zones.get_availability_zones(
             context, self.host_api, get_only_available=True)
         if availability_zone not in available_zones:
@@ -4443,31 +4459,88 @@ class API:
 
     @block_extended_resource_request
     @check_instance_lock
-    @check_instance_state(vm_state=[vm_states.SHELVED,
+    @check_instance_state(
-        vm_states.SHELVED_OFFLOADED])
+            vm_state=[vm_states.SHELVED, vm_states.SHELVED_OFFLOADED])
-    def unshelve(self, context, instance, new_az=None):
+    def unshelve(
-        """Restore a shelved instance."""
+            self, context, instance, new_az=_sentinel, host=None):
+        """Restore a shelved instance.
+
+        :param context: the nova request context
+        :param instance: nova.objects.instance.Instance object
+        :param new_az: (optional) target AZ.
+                       If None is provided then the current AZ restriction
+                       will be removed from the instance.
+                       If the parameter is not provided then the current
+                       AZ restriction will not be changed.
+        :param host: (optional) a host to target
+        """
+        # Unshelving a shelved offloaded server will go through the
+        # scheduler to pick a new host, so we update the
+        # RequestSpec.availability_zone here. Note that if scheduling
+        # fails the RequestSpec will remain updated, which is not great.
+        # Bug open to track this https://bugs.launchpad.net/nova/+bug/1978573
+
+        az_passed = new_az is not self._sentinel
+
         request_spec = objects.RequestSpec.get_by_instance_uuid(
             context, instance.uuid)
 
-        if new_az:
+        # We need to check a list of preconditions and validate inputs first
+
+        # Ensure instance is shelve offloaded
+        if az_passed or host:
+            self._check_offloaded(context, instance)
+
+        if az_passed and new_az:
+            # we have to ensure that new AZ is valid
             self._validate_unshelve_az(context, instance, new_az)
-            LOG.debug("Replace the old AZ %(old_az)s in RequestSpec "
+        # This will be the AZ of the instance after the unshelve. It can be
-                      "with a new AZ %(new_az)s of the instance.",
+        # None indicating that the instance is not pinned to any AZ after the
-                      {"old_az": request_spec.availability_zone,
+        # unshelve
-                       "new_az": new_az}, instance=instance)
+        expected_az_after_unshelve = (
-            # Unshelving a shelved offloaded server will go through the
+            request_spec.availability_zone
-            # scheduler to pick a new host, so we update the
+            if not az_passed else new_az
-            # RequestSpec.availability_zone here. Note that if scheduling
+        )
-            # fails the RequestSpec will remain updated, which is not great,
+        # host is requested, so we have to see if it exists and does not
-            # but if we want to change that we need to defer updating the
+        # contradict with the AZ of the instance
-            # RequestSpec until conductor which probably means RPC changes to
+        if host:
-            # pass the new_az variable to conductor. This is likely low
+            # Ensure that the requested host exists otherwise raise
-            # priority since the RequestSpec.availability_zone on a shelved
+            # a ComputeHostNotFound exception
-            # offloaded server does not mean much anyway and clearly the user
+            objects.ComputeNode.get_first_node_by_host_for_old_compat(
-            # is trying to put the server in the target AZ.
+                context, host, use_slave=True)
-            request_spec.availability_zone = new_az
+            # A specific host is requested so we need to make sure that it is
-            request_spec.save()
+            # not contradicts with the AZ of the instance
+            self._ensure_host_in_az(
+                context, host, expected_az_after_unshelve)
+
+        if new_az is None:
+            LOG.debug(
+                'Unpin instance from AZ "%(old_az)s".',
+                {'old_az': request_spec.availability_zone},
+                instance=instance
+            )
+
+        LOG.debug(
+            'Unshelving instance with old availability_zone "%(old_az)s" to '
+            'new availability_zone "%(new_az)s" and host "%(host)s".',
+            {
+                'old_az': request_spec.availability_zone,
+                'new_az': '%s' %
+                          new_az if az_passed
+                                 else 'not provided',
+                'host': host,
+             },
+            instance=instance,
+        )
+        # OK every precondition checks out, we just need to tell the scheduler
+        # where to put the instance
+        # We have the expected AZ already calculated. So we just need to
+        # set it in the request_spec to drive the scheduling
+        request_spec.availability_zone = expected_az_after_unshelve
+        # if host is requested we also need to tell the scheduler that
+        if host:
+            request_spec.requested_destination = objects.Destination(host=host)
+        request_spec.save()
 
         instance.task_state = task_states.UNSHELVING
         instance.save(expected_task_state=[None])

nova/conductor/manager.py

@@ -1022,6 +1022,12 @@ class ComputeTaskManager:
                     scheduler_utils.populate_filter_properties(
                             filter_properties, selection)
                     (host, node) = (selection.service_host, selection.nodename)
+                    LOG.debug(
+                        "Scheduler selected host: %s, node:%s",
+                        host,
+                        node,
+                        instance=instance
+                    )
                     instance.availability_zone = (
                         availability_zones.get_host_availability_zone(
                             context, host))

nova/exception.py

@@ -1676,9 +1676,15 @@ class MismatchVolumeAZException(Invalid):
 
 
 class UnshelveInstanceInvalidState(InstanceInvalidState):
-    msg_fmt = _('Specifying an availability zone when unshelving server '
+    msg_fmt = _('Specifying an availability zone or a host when unshelving '
-                '%(instance_uuid)s with status "%(state)s" is not supported. '
+                'server "%(instance_uuid)s" with status "%(state)s" is not '
-                'The server status must be SHELVED_OFFLOADED.')
+                'supported. The server status must be SHELVED_OFFLOADED.')
+    code = 409
+
+
+class UnshelveHostNotInAZ(Invalid):
+    msg_fmt = _('Host "%(host)s" is not in the availability zone '
+                '"%(availability_zone)s".')
     code = 409
 
 

nova/tests/unit/api/openstack/compute/test_shelve.py

@@ -140,7 +140,9 @@ class UnshelveServerControllerTestV277(test.NoDBTestCase):
                                'unshelve') as mock_unshelve:
             self.controller._unshelve(self.req, fakes.FAKE_UUID, body=body)
         mock_unshelve.assert_called_once_with(
-            self.req.environ['nova.context'], instance, new_az=None)
+            self.req.environ['nova.context'],
+            instance,
+        )
 
     @mock.patch('nova.compute.api.API.unshelve')
     @mock.patch('nova.api.openstack.common.get_instance')
@@ -158,7 +160,9 @@ class UnshelveServerControllerTestV277(test.NoDBTestCase):
                 APIVersionRequest('2.76'))
         self.controller._unshelve(self.req, fakes.FAKE_UUID, body=body)
         mock_unshelve.assert_called_once_with(
-            self.req.environ['nova.context'], instance, new_az=None)
+            self.req.environ['nova.context'],
+            instance,
+        )
 
     @mock.patch('nova.compute.api.API.unshelve')
     @mock.patch('nova.api.openstack.common.get_instance')

nova/tests/unit/compute/test_shelve.py

@@ -11,10 +11,10 @@
 #    under the License.
 
 import eventlet
-import mock
 from oslo_utils import fixture as utils_fixture
 from oslo_utils.fixture import uuidsentinel as uuids
 from oslo_utils import timeutils
+from unittest import mock
 
 from nova.compute import api as compute_api
 from nova.compute import claims
@@ -24,6 +24,7 @@ from nova.compute import task_states
 from nova.compute import utils as compute_utils
 from nova.compute import vm_states
 import nova.conf
+from nova import context
 from nova.db.main import api as db
 from nova import exception
 from nova.network import neutron as neutron_api
@@ -849,9 +850,67 @@ class ShelveComputeAPITestCase(test_compute.BaseTestCase):
             exclude_states = set()
         return vm_state - exclude_states
 
+    @mock.patch('nova.scheduler.client.report.SchedulerReportClient.'
+                'aggregate_add_host')
+    @mock.patch('nova.availability_zones.get_availability_zones')
+    def _create_host_inside_az(
+            self,
+            ctxt,
+            host,
+            az,
+            mock_az,
+            mock_aggregate,
+            ):
+
+        self.api = compute_api.AggregateAPI()
+        mock_az.return_value = [az]
+
+        cells = objects.CellMappingList.get_all(ctxt)
+        cell = cells[0]
+        with context.target_cell(ctxt, cell) as cctxt:
+            s = objects.Service(context=cctxt,
+                                host=host,
+                                binary='nova-compute',
+                                topic='compute',
+                                report_count=0)
+            s.create()
+
+        hm = objects.HostMapping(context=ctxt,
+                                 cell_mapping=cell,
+                                 host=host)
+        hm.create()
+
+        self._init_aggregate_with_host(None, 'fake_aggregate1',
+                                       az, host)
+
+    def _create_request_spec_for_initial_az(self, az):
+        fake_spec = objects.RequestSpec()
+        fake_spec.availability_zone = az
+        return fake_spec
+
+    def _assert_unshelving_and_request_spec_az_and_host(
+            self,
+            context,
+            instance,
+            fake_spec,
+            fake_zone,
+            fake_host,
+            mock_get_by_instance_uuid,
+            mock_unshelve
+    ):
+        mock_get_by_instance_uuid.assert_called_once_with(context,
+                                                     instance.uuid)
+
+        mock_unshelve.assert_called_once_with(context, instance, fake_spec)
+
+        self.assertEqual(instance.task_state, task_states.UNSHELVING)
+        self.assertEqual(fake_spec.availability_zone, fake_zone)
+        if fake_host:
+            self.assertEqual(fake_spec.requested_destination.host, fake_host)
+
     def _test_shelve(self, vm_state=vm_states.ACTIVE, boot_from_volume=False,
                      clean_shutdown=True):
-        # Ensure instance can be shelved.
+
         params = dict(task_state=None, vm_state=vm_state, display_name='vm01')
         fake_instance = self._create_fake_instance_obj(params=params)
         instance = fake_instance
@@ -988,12 +1047,14 @@ class ShelveComputeAPITestCase(test_compute.BaseTestCase):
 
         return instance
 
+    @mock.patch.object(objects.RequestSpec, 'save')
     @mock.patch.object(objects.RequestSpec, 'get_by_instance_uuid')
-    def test_unshelve(self, get_by_instance_uuid):
+    def test_unshelve(self, get_by_instance_uuid, fake_save):
         # Ensure instance can be unshelved.
         instance = self._get_specify_state_instance(vm_states.SHELVED)
 
         fake_spec = objects.RequestSpec()
+        fake_spec.availability_zone = None
         get_by_instance_uuid.return_value = fake_spec
         with mock.patch.object(self.compute_api.compute_task_api,
                                'unshelve_instance') as unshelve:
@@ -1116,24 +1177,558 @@ class ShelveComputeAPITestCase(test_compute.BaseTestCase):
         mock_get_bdms.assert_called_once_with(self.context, instance.uuid)
         mock_get.assert_called_once_with(self.context, uuids.volume_id)
 
-    @mock.patch.object(compute_api.API, '_validate_unshelve_az')
+# Next tests attempt to check the following behavior
+# +----------+---------------------------+-------+----------------------------+
+# | Boot     | Unshelve after offload AZ | Host  | Result                     |
+# +==========+===========================+=======+============================+
+# |  No AZ   | No AZ or AZ=null          | No    | Free scheduling,           |
+# |          |                           |       | reqspec.AZ=None            |
+# +----------+---------------------------+-------+----------------------------+
+# |  No AZ   | No AZ or AZ=null          | Host1 | Schedule to host1,         |
+# |          |                           |       | reqspec.AZ=None            |
+# +----------+---------------------------+-------+----------------------------+
+# |  No AZ   | AZ="AZ1"                  | No    | Schedule to AZ1,           |
+# |          |                           |       | reqspec.AZ="AZ1"           |
+# +----------+---------------------------+-------+----------------------------+
+# |  No AZ   | AZ="AZ1"                  | Host1 | Verify that host1 in AZ1,  |
+# |          |                           |       | or (1). Schedule to        |
+# |          |                           |       | host1, reqspec.AZ="AZ1"    |
+# +----------+---------------------------+-------+----------------------------+
+# |  AZ1     | No AZ                     | No    | Schedule to AZ1,           |
+# |          |                           |       | reqspec.AZ="AZ1"           |
+# +----------+---------------------------+-------+----------------------------+
+# |  AZ1     | AZ=null                   | No    | Free scheduling,           |
+# |          |                           |       | reqspec.AZ=None            |
+# +----------+---------------------------+-------+----------------------------+
+# |  AZ1     | No AZ                     | Host1 | If host1 is in AZ1,        |
+# |          |                           |       | then schedule to host1,    |
+# |          |                           |       | reqspec.AZ="AZ1", otherwise|
+# |          |                           |       | reject the request (1)     |
+# +----------+---------------------------+-------+----------------------------+
+# |  AZ1     | AZ=null                   | Host1 | Schedule to host1,         |
+# |          |                           |       | reqspec.AZ=None            |
+# +----------+---------------------------+-------+----------------------------+
+# |  AZ1     | AZ="AZ2"                  | No    | Schedule to AZ2,           |
+# |          |                           |       | reqspec.AZ="AZ2"           |
+# +----------+---------------------------+-------+----------------------------+
+# |  AZ1     | AZ="AZ2"                  | Host1 | If host1 in AZ2 then       |
+# |          |                           |       | schedule to host1,         |
+# |          |                           |       | reqspec.AZ="AZ2",          |
+# |          |                           |       | otherwise reject (1)       |
+# +----------+---------------------------+-------+----------------------------+
+#
+# (1) Check at the api and return an error.
+#
+#
+# +----------+---------------------------+-------+----------------------------+
+# |  No AZ   | No AZ or AZ=null          | No    | Free scheduling,           |
+# |          |                           |       | reqspec.AZ=None            |
+# +----------+---------------------------+-------+----------------------------+
+    @mock.patch.object(nova.conductor.ComputeTaskAPI, 'unshelve_instance')
     @mock.patch.object(objects.RequestSpec, 'save')
+    @mock.patch.object(objects.ComputeNodeList, 'get_all_by_host')
     @mock.patch.object(objects.RequestSpec, 'get_by_instance_uuid')
-    def test_specified_az_unshelve(self, get_by_instance_uuid,
+    def test_unshelve_without_az(
-                                   mock_save, mock_validate_unshelve_az):
+            self,
-        # Ensure instance can be unshelved.
+            mock_get_by_instance_uuid,
+            mock_get_all_by_host,
+            mock_save,
+            mock_unshelve
+        ):
+
+        context = self.context.elevated()
+        fake_host = 'fake_host1'
+        fake_zone = 'avail_zone1'
+        self._create_host_inside_az(self.context, fake_host, fake_zone)
+
         instance = self._get_specify_state_instance(
             vm_states.SHELVED_OFFLOADED)
 
-        new_az = "west_az"
+        fake_spec = self._create_request_spec_for_initial_az(None)
-        fake_spec = objects.RequestSpec()
+        mock_get_by_instance_uuid.return_value = fake_spec
-        fake_spec.availability_zone = "fake-old-az"
-        get_by_instance_uuid.return_value = fake_spec
 
-        self.compute_api.unshelve(self.context, instance, new_az=new_az)
+        self.compute_api.unshelve(context, instance)
 
-        mock_save.assert_called_once_with()
+        self._assert_unshelving_and_request_spec_az_and_host(
-        self.assertEqual(new_az, fake_spec.availability_zone)
+            context,
+            instance,
+            fake_spec,
+            None,
+            None,
+            mock_get_by_instance_uuid,
+            mock_unshelve
+        )
 
-        mock_validate_unshelve_az.assert_called_once_with(
+# +----------+---------------------------+-------+----------------------------+
-            self.context, instance, new_az)
+# |  No AZ   | No AZ or AZ=null          | Host1 | Schedule to host1,         |
+# |          |                           |       | reqspec.AZ=None            |
+# +----------+---------------------------+-------+----------------------------+
+    @mock.patch.object(nova.conductor.ComputeTaskAPI, 'unshelve_instance')
+    @mock.patch.object(objects.RequestSpec, 'save')
+    @mock.patch.object(objects.ComputeNodeList, 'get_all_by_host')
+    @mock.patch.object(objects.RequestSpec, 'get_by_instance_uuid')
+    def test_unshelve_without_az_to_host(
+            self,
+            mock_get_by_instance_uuid,
+            mock_get_all_by_host,
+            mock_save,
+            mock_unshelve
+        ):
+
+        context = self.context.elevated()
+        fake_host = 'fake_host1'
+        fake_zone = 'avail_zone1'
+        self._create_host_inside_az(self.context, fake_host, fake_zone)
+
+        instance = self._get_specify_state_instance(
+            vm_states.SHELVED_OFFLOADED)
+
+        fake_spec = self._create_request_spec_for_initial_az(None)
+        mock_get_by_instance_uuid.return_value = fake_spec
+
+        self.compute_api.unshelve(context, instance, host=fake_host)
+
+        self._assert_unshelving_and_request_spec_az_and_host(
+            context,
+            instance,
+            fake_spec,
+            None,
+            fake_host,
+            mock_get_by_instance_uuid,
+            mock_unshelve
+        )
+
+# +----------+---------------------------+-------+----------------------------+
+# |  No AZ   | AZ="AZ1"                  | No    | Schedule to AZ1,           |
+# |          |                           |       | reqspec.AZ="AZ1"           |
+# +----------+---------------------------+-------+----------------------------+
+    @mock.patch.object(nova.conductor.ComputeTaskAPI, 'unshelve_instance')
+    @mock.patch.object(objects.RequestSpec, 'save')
+    @mock.patch.object(objects.ComputeNodeList, 'get_all_by_host')
+    @mock.patch.object(objects.RequestSpec, 'get_by_instance_uuid')
+    def test_unshelve_without_az_to_newaz(
+            self,
+            mock_get_by_instance_uuid,
+            mock_get_all_by_host,
+            mock_save,
+            mock_unshelve
+        ):
+
+        context = self.context.elevated()
+        fake_host = 'fake_host1'
+        fake_zone = 'avail_zone1'
+        self._create_host_inside_az(self.context, fake_host, fake_zone)
+
+        instance = self._get_specify_state_instance(
+            vm_states.SHELVED_OFFLOADED)
+
+        fake_spec = self._create_request_spec_for_initial_az(None)
+        mock_get_by_instance_uuid.return_value = fake_spec
+
+        self.compute_api.unshelve(context, instance, new_az=fake_zone)
+
+        self._assert_unshelving_and_request_spec_az_and_host(
+            context,
+            instance,
+            fake_spec,
+            fake_zone,
+            None,
+            mock_get_by_instance_uuid,
+            mock_unshelve
+        )
+
+# +----------+---------------------------+-------+----------------------------+
+# |  No AZ   | AZ="AZ1"                  | Host1 | Verify that host1 in AZ1,  |
+# |          |                           |       | or (1). Schedule to        |
+# |          |                           |       | host1, reqspec.AZ="AZ1"    |
+# +----------+---------------------------+-------+----------------------------+
+    @mock.patch.object(nova.conductor.ComputeTaskAPI, 'unshelve_instance')
+    @mock.patch.object(objects.RequestSpec, 'save')
+    @mock.patch.object(objects.ComputeNodeList, 'get_all_by_host')
+    @mock.patch.object(objects.RequestSpec, 'get_by_instance_uuid')
+    def test_unshelve_without_az_to_newaz_and_host(
+            self,
+            mock_get_by_instance_uuid,
+            mock_get_all_by_host,
+            mock_save,
+            mock_unshelve
+        ):
+
+        context = self.context.elevated()
+        fake_host = 'fake_host1'
+        fake_zone = 'avail_zone1'
+        self._create_host_inside_az(self.context, fake_host, fake_zone)
+
+        instance = self._get_specify_state_instance(
+            vm_states.SHELVED_OFFLOADED)
+
+        fake_spec = self._create_request_spec_for_initial_az(None)
+        mock_get_by_instance_uuid.return_value = fake_spec
+
+        self.compute_api.unshelve(
+            context, instance, new_az=fake_zone, host=fake_host
+        )
+
+        self._assert_unshelving_and_request_spec_az_and_host(
+            context,
+            instance,
+            fake_spec,
+            fake_zone,
+            fake_host,
+            mock_get_by_instance_uuid,
+            mock_unshelve
+        )
+
+    @mock.patch.object(nova.conductor.ComputeTaskAPI, 'unshelve_instance')
+    @mock.patch.object(objects.RequestSpec, 'save')
+    @mock.patch.object(objects.ComputeNodeList, 'get_all_by_host')
+    @mock.patch.object(objects.RequestSpec, 'get_by_instance_uuid')
+    def test_unshelve_without_az_to_newaz_and_host_invalid(
+            self,
+            mock_get_by_instance_uuid,
+            mock_get_all_by_host,
+            mock_save,
+            mock_unshelve
+        ):
+
+        context = self.context.elevated()
+        fake_host = 'fake_host1'
+        fake_zone = 'avail_zone1'
+        self._create_host_inside_az(self.context, fake_host, fake_zone)
+
+        instance = self._get_specify_state_instance(
+            vm_states.SHELVED_OFFLOADED)
+
+        fake_spec = self._create_request_spec_for_initial_az(None)
+        mock_get_by_instance_uuid.return_value = fake_spec
+
+        exc = self.assertRaises(
+            nova.exception.UnshelveHostNotInAZ,
+            self.compute_api.unshelve,
+            context,
+            instance,
+            new_az='avail_zone1',
+            host='fake_mini'
+        )
+
+        self.assertIn(
+            exc.message,
+            'Host "fake_mini" is not in the availability zone "avail_zone1".'
+        )
+
+# +----------+---------------------------+-------+----------------------------+
+# |  AZ1     | No AZ                     | No    | Schedule to AZ1,           |
+# |          |                           |       | reqspec.AZ="AZ1"           |
+# +----------+---------------------------+-------+----------------------------+
+    @mock.patch.object(nova.conductor.ComputeTaskAPI, 'unshelve_instance')
+    @mock.patch.object(objects.RequestSpec, 'save')
+    @mock.patch.object(objects.ComputeNodeList, 'get_all_by_host')
+    @mock.patch.object(objects.RequestSpec, 'get_by_instance_uuid')
+    def test_unshelve_with_az(
+            self,
+            mock_get_by_instance_uuid,
+            mock_get_all_by_host,
+            mock_save,
+            mock_unshelve
+        ):
+
+        context = self.context.elevated()
+        fake_host = 'fake_host1'
+        fake_zone = 'avail_zone1'
+        self._create_host_inside_az(self.context, fake_host, fake_zone)
+
+        instance = self._get_specify_state_instance(
+            vm_states.SHELVED_OFFLOADED)
+
+        fake_spec = self._create_request_spec_for_initial_az(fake_zone)
+        mock_get_by_instance_uuid.return_value = fake_spec
+
+        self.compute_api.unshelve(context, instance)
+
+        self._assert_unshelving_and_request_spec_az_and_host(
+            context,
+            instance,
+            fake_spec,
+            fake_zone,
+            None,
+            mock_get_by_instance_uuid,
+            mock_unshelve
+        )
+
+# +----------+---------------------------+-------+----------------------------+
+# |  AZ1     | AZ=null                   | No    | Free scheduling,           |
+# |          |                           |       | reqspec.AZ=None            |
+# +----------+---------------------------+-------+----------------------------+
+    @mock.patch.object(nova.conductor.ComputeTaskAPI, 'unshelve_instance')
+    @mock.patch.object(objects.RequestSpec, 'save')
+    @mock.patch.object(objects.ComputeNodeList, 'get_all_by_host')
+    @mock.patch.object(objects.RequestSpec, 'get_by_instance_uuid')
+    def test_unshelve_with_az_to_unpin_az(
+            self,
+            mock_get_by_instance_uuid,
+            mock_get_all_by_host,
+            mock_save,
+            mock_unshelve
+        ):
+
+        context = self.context.elevated()
+        fake_host = 'fake_host1'
+        fake_zone = 'avail_zone1'
+        self._create_host_inside_az(self.context, fake_host, fake_zone)
+
+        instance = self._get_specify_state_instance(
+            vm_states.SHELVED_OFFLOADED)
+
+        fake_spec = self._create_request_spec_for_initial_az(fake_zone)
+        mock_get_by_instance_uuid.return_value = fake_spec
+
+        self.compute_api.unshelve(context, instance, new_az=None)
+
+        self._assert_unshelving_and_request_spec_az_and_host(
+            context,
+            instance,
+            fake_spec,
+            None,
+            None,
+            mock_get_by_instance_uuid,
+            mock_unshelve
+        )
+
+# +----------+---------------------------+-------+----------------------------+
+# |  AZ1     | No AZ                     | Host1 | If host1 is in AZ1,        |
+# |          |                           |       | then schedule to host1,    |
+# |          |                           |       | reqspec.AZ="AZ1", otherwise|
+# |          |                           |       | reject the request (1)     |
+# +----------+---------------------------+-------+----------------------------+
+    @mock.patch.object(nova.conductor.ComputeTaskAPI, 'unshelve_instance')
+    @mock.patch.object(objects.RequestSpec, 'save')
+    @mock.patch.object(objects.ComputeNodeList, 'get_all_by_host')
+    @mock.patch.object(objects.RequestSpec, 'get_by_instance_uuid')
+    def test_unshelve_with_az_to_host_in_az(
+            self,
+            mock_get_by_instance_uuid,
+            mock_get_all_by_host,
+            mock_save,
+            mock_unshelve
+        ):
+
+        context = self.context.elevated()
+        fake_host = 'fake_host1'
+        fake_zone = 'avail_zone1'
+        self._create_host_inside_az(self.context, fake_host, fake_zone)
+
+        instance = self._get_specify_state_instance(
+            vm_states.SHELVED_OFFLOADED)
+
+        fake_spec = self._create_request_spec_for_initial_az(fake_zone)
+        mock_get_by_instance_uuid.return_value = fake_spec
+
+        self.compute_api.unshelve(context, instance, host=fake_host)
+
+        self._assert_unshelving_and_request_spec_az_and_host(
+            context,
+            instance,
+            fake_spec,
+            fake_zone,
+            fake_host,
+            mock_get_by_instance_uuid,
+            mock_unshelve
+        )
+
+    @mock.patch.object(nova.conductor.ComputeTaskAPI, 'unshelve_instance')
+    @mock.patch.object(objects.RequestSpec, 'save')
+    @mock.patch.object(objects.ComputeNodeList, 'get_all_by_host')
+    @mock.patch.object(objects.RequestSpec, 'get_by_instance_uuid')
+    def test_unshelve_with_az_to_invalid_host(
+            self,
+            mock_get_by_instance_uuid,
+            mock_get_all_by_host,
+            mock_save,
+            mock_unshelve
+        ):
+
+        context = self.context.elevated()
+        fake_host = 'fake_host1'
+        fake_zone = 'avail_zone1'
+        self._create_host_inside_az(self.context, fake_host, fake_zone)
+
+        instance = self._get_specify_state_instance(
+            vm_states.SHELVED_OFFLOADED)
+
+        fake_spec = self._create_request_spec_for_initial_az(fake_zone)
+        mock_get_by_instance_uuid.return_value = fake_spec
+
+        exc = self.assertRaises(
+            nova.exception.UnshelveHostNotInAZ,
+            self.compute_api.unshelve,
+            context,
+            instance,
+            host='fake_mini'
+        )
+
+        self.assertIn(
+            exc.message,
+            'Host "fake_mini" is not in the availability zone "avail_zone1".'
+        )
+
+# +----------+---------------------------+-------+----------------------------+
+# |  AZ1     | AZ=null                   | Host1 | Schedule to host1,         |
+# |          |                           |       | reqspec.AZ=None            |
+# +----------+---------------------------+-------+----------------------------+
+    @mock.patch.object(nova.conductor.ComputeTaskAPI, 'unshelve_instance')
+    @mock.patch.object(objects.RequestSpec, 'save')
+    @mock.patch.object(objects.ComputeNodeList, 'get_all_by_host')
+    @mock.patch.object(objects.RequestSpec, 'get_by_instance_uuid')
+    def test_unshelve_with_az_to_host_unpin_az(
+            self,
+            mock_get_by_instance_uuid,
+            mock_get_all_by_host,
+            mock_save,
+            mock_unshelve
+        ):
+
+        context = self.context.elevated()
+        fake_host = 'fake_host1'
+        fake_zone = 'avail_zone1'
+        self._create_host_inside_az(self.context, fake_host, fake_zone)
+
+        instance = self._get_specify_state_instance(
+            vm_states.SHELVED_OFFLOADED)
+
+        fake_spec = self._create_request_spec_for_initial_az(fake_zone)
+        mock_get_by_instance_uuid.return_value = fake_spec
+
+        self.compute_api.unshelve(
+            context, instance, new_az=None, host=fake_host
+        )
+
+        self._assert_unshelving_and_request_spec_az_and_host(
+            context,
+            instance,
+            fake_spec,
+            None,
+            fake_host,
+            mock_get_by_instance_uuid,
+            mock_unshelve
+        )
+
+# +----------+---------------------------+-------+----------------------------+
+# |  AZ1     | AZ="AZ2"                  | No    | Schedule to AZ2,           |
+# |          |                           |       | reqspec.AZ="AZ2"           |
+# +----------+---------------------------+-------+----------------------------+
+    @mock.patch.object(nova.conductor.ComputeTaskAPI, 'unshelve_instance')
+    @mock.patch.object(objects.RequestSpec, 'save')
+    @mock.patch.object(objects.ComputeNodeList, 'get_all_by_host')
+    @mock.patch.object(objects.RequestSpec, 'get_by_instance_uuid')
+    def test_unshelve_with_az_to_newaz(
+            self,
+            mock_get_by_instance_uuid,
+            mock_get_all_by_host,
+            mock_save,
+            mock_unshelve
+        ):
+
+        context = self.context.elevated()
+        fake_host = 'fake_host1'
+        fake_zone = 'avail_zone1'
+        self._create_host_inside_az(self.context, fake_host, fake_zone)
+
+        instance = self._get_specify_state_instance(
+            vm_states.SHELVED_OFFLOADED)
+
+        fake_spec = self._create_request_spec_for_initial_az('az1')
+        mock_get_by_instance_uuid.return_value = fake_spec
+
+        self.compute_api.unshelve(
+            context, instance, new_az=fake_zone
+        )
+
+        self._assert_unshelving_and_request_spec_az_and_host(
+            context,
+            instance,
+            fake_spec,
+            fake_zone,
+            None,
+            mock_get_by_instance_uuid,
+            mock_unshelve
+        )
+
+# +----------+---------------------------+-------+----------------------------+
+# |  AZ1     | AZ="AZ2"                  | Host1 | If host1 in AZ2 then       |
+# |          |                           |       | schedule to host1,         |
+# |          |                           |       | reqspec.AZ="AZ2",          |
+# |          |                           |       | otherwise reject (1)       |
+# +----------+---------------------------+-------+----------------------------+
+    @mock.patch.object(nova.conductor.ComputeTaskAPI, 'unshelve_instance')
+    @mock.patch.object(objects.RequestSpec, 'save')
+    @mock.patch.object(objects.ComputeNodeList, 'get_all_by_host')
+    @mock.patch.object(objects.RequestSpec, 'get_by_instance_uuid')
+    def test_unshelve_with_az_to_newaz_and_host(
+            self,
+            mock_get_by_instance_uuid,
+            mock_get_all_by_host,
+            mock_save,
+            mock_unshelve
+        ):
+
+        context = self.context.elevated()
+        fake_host = 'fake_host1'
+        fake_zone = 'avail_zone1'
+        self._create_host_inside_az(self.context, fake_host, fake_zone)
+
+        instance = self._get_specify_state_instance(
+            vm_states.SHELVED_OFFLOADED)
+
+        fake_spec = self._create_request_spec_for_initial_az('az1')
+        mock_get_by_instance_uuid.return_value = fake_spec
+
+        self.compute_api.unshelve(
+            context, instance, new_az=fake_zone, host=fake_host
+        )
+
+        self._assert_unshelving_and_request_spec_az_and_host(
+            context,
+            instance,
+            fake_spec,
+            fake_zone,
+            fake_host,
+            mock_get_by_instance_uuid,
+            mock_unshelve
+        )
+
+    @mock.patch.object(nova.conductor.ComputeTaskAPI, 'unshelve_instance')
+    @mock.patch.object(objects.RequestSpec, 'save')
+    @mock.patch.object(objects.ComputeNodeList, 'get_all_by_host')
+    @mock.patch.object(objects.RequestSpec, 'get_by_instance_uuid')
+    def test_unshelve_with_az_to_newaz_and_invalid_host(
+            self,
+            mock_get_by_instance_uuid,
+            mock_get_all_by_host,
+            mock_save,
+            mock_unshelve
+        ):
+
+        context = self.context.elevated()
+        fake_host = 'fake_host1'
+        fake_zone = 'avail_zone1'
+        self._create_host_inside_az(self.context, fake_host, fake_zone)
+
+        instance = self._get_specify_state_instance(
+            vm_states.SHELVED_OFFLOADED)
+
+        fake_spec = self._create_request_spec_for_initial_az('az1')
+        mock_get_by_instance_uuid.return_value = fake_spec
+
+        exc = self.assertRaises(
+            nova.exception.UnshelveHostNotInAZ,
+            self.compute_api.unshelve,
+            context,
+            instance,
+            new_az=fake_zone,
+            host='fake_mini'
+        )
+
+        self.assertIn(
+            exc.message,
+            'Host "fake_mini" is not in the availability zone "avail_zone1".'
+        )