diff --git a/nova/cmd/manage.py b/nova/cmd/manage.py
index 2cb7aed90d7d..1cdc81f4d031 100644
--- a/nova/cmd/manage.py
+++ b/nova/cmd/manage.py
@@ -1687,10 +1687,16 @@ class CellV2Commands(object):
         # Check to see if there are any HostMappings for this cell.
         host_mappings = objects.HostMappingList.get_by_cell_id(
             ctxt, cell_mapping.id)
-        if host_mappings and not force:
-            print(_('There are existing hosts mapped to cell with uuid %s.') %
-                  cell_uuid)
-            return 2
+        nodes = []
+        if host_mappings:
+            if not force:
+                print(_('There are existing hosts mapped to cell with uuid '
+                        '%s.') % cell_uuid)
+                return 2
+            # We query for the compute nodes in the cell,
+            # so that they can be unmapped.
+            with context.target_cell(ctxt, cell_mapping) as cctxt:
+                nodes = objects.ComputeNodeList.get_all(cctxt)
 
         # Check to see if there are any InstanceMappings for this cell.
         instance_mappings = objects.InstanceMappingList.get_by_cell_id(
@@ -1700,6 +1706,12 @@ class CellV2Commands(object):
                     'uuid %s.') % cell_uuid)
             return 3
 
+        # Unmap the compute nodes so that they can be discovered
+        # again in future, if needed.
+        for node in nodes:
+            node.mapped = 0
+            node.save()
+
         # Delete hosts mapped to the cell.
         for host_mapping in host_mappings:
             host_mapping.destroy()
diff --git a/nova/tests/functional/test_nova_manage.py b/nova/tests/functional/test_nova_manage.py
index 08cde5fbeae7..4bb21bb3bc22 100644
--- a/nova/tests/functional/test_nova_manage.py
+++ b/nova/tests/functional/test_nova_manage.py
@@ -12,6 +12,7 @@
 
 from nova.cmd import manage
 from nova import context
+from nova import exception
 from nova import objects
 from nova import test
 
@@ -317,3 +318,33 @@ class NovaManageCellV2Test(test.TestCase):
         cns = objects.ComputeNodeList.get_all(self.context)
         self.assertEqual(1, len(cns))
         self.assertEqual(0, cns[0].mapped)
+
+    def test_delete_cell_force_unmaps_computes(self):
+        cells = objects.CellMappingList.get_all(self.context)
+
+        self.commands.discover_hosts()
+
+        # We should have one host mapping
+        objects.HostMapping.get_by_host(self.context, 'fake-host1')
+
+        # We should have one mapped node
+        cns = objects.ComputeNodeList.get_all(self.context)
+        self.assertEqual(1, len(cns))
+        self.assertEqual(1, cns[0].mapped)
+
+        for cell in cells:
+            res = self.commands.delete_cell(cell.uuid, force=True)
+            self.assertEqual(0, res)
+
+        # The host mapping should be deleted since the force option is used
+        self.assertRaises(exception.HostMappingNotFound,
+            objects.HostMapping.get_by_host, self.context, 'fake-host1')
+
+        # All our cells should be deleted
+        cells = objects.CellMappingList.get_all(self.context)
+        self.assertEqual(0, len(cells))
+
+        # Our node should now be unmapped
+        cns = objects.ComputeNodeList.get_all(self.context)
+        self.assertEqual(1, len(cns))
+        self.assertEqual(0, cns[0].mapped)
diff --git a/nova/tests/unit/test_nova_manage.py b/nova/tests/unit/test_nova_manage.py
index cf2933891408..d145c19226ce 100644
--- a/nova/tests/unit/test_nova_manage.py
+++ b/nova/tests/unit/test_nova_manage.py
@@ -1574,7 +1574,8 @@ class CellV2CommandsTestCase(test.NoDBTestCase):
         self.assertEqual('Cell with uuid %s was not found.' % cell_uuid,
                          output)
 
-    def test_delete_cell_host_mappings_exist(self):
+    @mock.patch.object(objects.ComputeNodeList, 'get_all')
+    def test_delete_cell_host_mappings_exist(self, mock_get_cn):
         """Tests trying to delete a cell which has host mappings."""
         cell_uuid = uuidutils.generate_uuid()
         ctxt = context.get_admin_context()
@@ -1587,6 +1588,7 @@ class CellV2CommandsTestCase(test.NoDBTestCase):
         hm = objects.HostMapping(
             context=ctxt, host='fake-host', cell_mapping=cm)
         hm.create()
+        mock_get_cn.return_value = []
         self.assertEqual(2, self.commands.delete_cell(cell_uuid))
         output = self.output.getvalue().strip()
         self.assertIn('There are existing hosts mapped to cell', output)
@@ -1622,10 +1624,11 @@ class CellV2CommandsTestCase(test.NoDBTestCase):
         output = self.output.getvalue().strip()
         self.assertEqual('', output)
 
+    @mock.patch.object(objects.ComputeNodeList, 'get_all')
     @mock.patch.object(objects.HostMapping, 'destroy')
     @mock.patch.object(objects.CellMapping, 'destroy')
     def test_delete_cell_success_with_host_mappings(self, mock_cell_destroy,
-                                                    mock_hm_destroy):
+                                            mock_hm_destroy, mock_get_cn):
         """Tests trying to delete a cell with host."""
         ctxt = context.get_admin_context()
         # create the cell mapping
@@ -1637,6 +1640,7 @@ class CellV2CommandsTestCase(test.NoDBTestCase):
         hm = objects.HostMapping(
             context=ctxt, host='fake-host', cell_mapping=cm)
         hm.create()
+        mock_get_cn.return_value = []
         self.assertEqual(0, self.commands.delete_cell(uuidsentinel.cell1,
                                                       force=True))
         output = self.output.getvalue().strip()