diff --git a/nova/compute/api.py b/nova/compute/api.py
index 8c38a3b7391b..6356d1386d00 100644
--- a/nova/compute/api.py
+++ b/nova/compute/api.py
@@ -3981,6 +3981,11 @@ class API(base.Base):
         LOG.debug("Going to try to live migrate instance to %s",
                   host_name or "another host", instance=instance)
 
+        if host_name:
+            # Validate the specified host before changing the instance task
+            # state.
+            nodes = objects.ComputeNodeList.get_all_by_host(context, host_name)
+
         instance.task_state = task_states.MIGRATING
         instance.save(expected_task_state=[None])
 
@@ -4000,7 +4005,6 @@ class API(base.Base):
 
         # NOTE(sbauza): Force is a boolean by the new related API version
         if force is False and host_name:
-            nodes = objects.ComputeNodeList.get_all_by_host(context, host_name)
             # Unset the host to make sure we call the scheduler
             # from the conductor LiveMigrationTask. Yes this is tightly-coupled
             # to behavior in conductor and not great.
diff --git a/nova/tests/unit/compute/test_compute_api.py b/nova/tests/unit/compute/test_compute_api.py
index f164ad6351c9..7d548792c028 100644
--- a/nova/tests/unit/compute/test_compute_api.py
+++ b/nova/tests/unit/compute/test_compute_api.py
@@ -2224,21 +2224,25 @@ class _ComputeAPIUnitTestMixIn(object):
                           self.compute_api.get_instance_diagnostics,
                           self.context, instance)
 
-    def test_live_migrate_active_vm_state(self):
+    @mock.patch.object(objects.ComputeNodeList, 'get_all_by_host')
+    def test_live_migrate_active_vm_state(self, mock_nodelist):
         instance = self._create_instance_obj()
         self._live_migrate_instance(instance)
 
-    def test_live_migrate_paused_vm_state(self):
+    @mock.patch.object(objects.ComputeNodeList, 'get_all_by_host')
+    def test_live_migrate_paused_vm_state(self, mock_nodelist):
         paused_state = dict(vm_state=vm_states.PAUSED)
         instance = self._create_instance_obj(params=paused_state)
         self._live_migrate_instance(instance)
 
+    @mock.patch.object(objects.ComputeNodeList, 'get_all_by_host')
     @mock.patch.object(compute_utils, 'add_instance_fault_from_exc')
     @mock.patch.object(objects.RequestSpec, 'get_by_instance_uuid')
     @mock.patch.object(objects.InstanceAction, 'action_start')
     @mock.patch.object(objects.Instance, 'save')
     def test_live_migrate_messaging_timeout(self, _save, _action, get_spec,
-                                            add_instance_fault_from_exc):
+                                            add_instance_fault_from_exc,
+                                            mock_nodelist):
         instance = self._create_instance_obj()
         if self.cell_type == 'api':
             api = self.compute_api.cells_rpcapi
@@ -2257,6 +2261,23 @@ class _ComputeAPIUnitTestMixIn(object):
                 instance,
                 mock.ANY)
 
+    @mock.patch.object(objects.RequestSpec, 'get_by_instance_uuid')
+    @mock.patch.object(objects.InstanceAction, 'action_start')
+    @mock.patch.object(objects.ComputeNodeList, 'get_all_by_host',
+                       side_effect=exception.ComputeHostNotFound(
+                           host='fake_host'))
+    def test_live_migrate_computehost_notfound(self, mock_nodelist,
+                                               mock_action,
+                                               mock_get_spec):
+        instance = self._create_instance_obj()
+        self.assertRaises(exception.ComputeHostNotFound,
+                          self.compute_api.live_migrate,
+                          self.context, instance,
+                          host_name='fake_host',
+                          block_migration='auto',
+                          disk_over_commit=False)
+        self.assertIsNone(instance.task_state)
+
     @mock.patch.object(objects.RequestSpec, 'get_by_instance_uuid')
     @mock.patch.object(objects.Instance, 'save')
     @mock.patch.object(objects.InstanceAction, 'action_start')
diff --git a/nova/tests/unit/compute/test_compute_cells.py b/nova/tests/unit/compute/test_compute_cells.py
index ff82bf67fa34..52a2a5f0ee8d 100644
--- a/nova/tests/unit/compute/test_compute_cells.py
+++ b/nova/tests/unit/compute/test_compute_cells.py
@@ -672,10 +672,12 @@ class CellsConductorAPIRPCRedirect(test.NoDBTestCase):
         self.compute_api.resize(self.context, instance)
         self.assertTrue(self.cells_rpcapi.resize_instance.called)
 
+    @mock.patch.object(objects.ComputeNodeList, 'get_all_by_host')
     @mock.patch.object(objects.RequestSpec, 'get_by_instance_uuid')
     @mock.patch.object(compute_api.API, '_record_action_start')
     @mock.patch.object(objects.Instance, 'save')
-    def test_live_migrate_instance(self, instance_save, _record, _get_spec):
+    def test_live_migrate_instance(self, instance_save, _record, _get_spec,
+                                   mock_nodelist):
         orig_system_metadata = {}
         instance = fake_instance.fake_instance_obj(self.context,
                 vm_state=vm_states.ACTIVE, cell_name='fake-cell',