diff --git a/nova/tests/test_imagebackend.py b/nova/tests/test_imagebackend.py
index d571bbf9ed2..4ec36daa8c4 100644
--- a/nova/tests/test_imagebackend.py
+++ b/nova/tests/test_imagebackend.py
@@ -20,6 +20,7 @@
 import fixtures
 from oslo.config import cfg
 
+from nova import exception
 from nova.openstack.common import uuidutils
 from nova import test
 from nova.tests import fake_libvirt_utils
@@ -253,9 +254,12 @@ def test_create_image_with_size(self):
         fn = self.prepare_mocks()
         fn(target=self.TEMPLATE_PATH)
         self.mox.StubOutWithMock(os.path, 'exists')
+        self.mox.StubOutWithMock(imagebackend.disk, 'get_disk_size')
         if self.OLD_STYLE_INSTANCE_PATH:
             os.path.exists(self.OLD_STYLE_INSTANCE_PATH).AndReturn(False)
         os.path.exists(self.TEMPLATE_PATH).AndReturn(False)
+        imagebackend.disk.get_disk_size(self.TEMPLATE_PATH
+                                       ).AndReturn(self.SIZE)
         os.path.exists(self.PATH).AndReturn(False)
         imagebackend.libvirt_utils.create_cow_image(self.TEMPLATE_PATH,
                                                     self.PATH)
@@ -267,6 +271,23 @@ def test_create_image_with_size(self):
 
         self.mox.VerifyAll()
 
+    def test_create_image_too_small(self):
+        fn = self.prepare_mocks()
+        fn(target=self.TEMPLATE_PATH)
+        self.mox.StubOutWithMock(os.path, 'exists')
+        self.mox.StubOutWithMock(imagebackend.disk, 'get_disk_size')
+        if self.OLD_STYLE_INSTANCE_PATH:
+            os.path.exists(self.OLD_STYLE_INSTANCE_PATH).AndReturn(False)
+        os.path.exists(self.TEMPLATE_PATH).AndReturn(False)
+        imagebackend.disk.get_disk_size(self.TEMPLATE_PATH
+                                       ).AndReturn(self.SIZE)
+        self.mox.ReplayAll()
+
+        image = self.image_class(self.INSTANCE, self.NAME)
+        self.assertRaises(exception.ImageTooLarge, image.create_image, fn,
+                          self.TEMPLATE_PATH, 1)
+        self.mox.VerifyAll()
+
 
 class LvmTestCase(_ImageTestCase, test.TestCase):
     VG = 'FakeVG'
diff --git a/nova/virt/libvirt/imagebackend.py b/nova/virt/libvirt/imagebackend.py
index b6b1b88aaa6..2ca71cc62cc 100755
--- a/nova/virt/libvirt/imagebackend.py
+++ b/nova/virt/libvirt/imagebackend.py
@@ -21,6 +21,7 @@
 
 from oslo.config import cfg
 
+from nova import exception
 from nova.openstack.common import excutils
 from nova.openstack.common import fileutils
 from nova.openstack.common import lockutils
@@ -255,6 +256,13 @@ def copy_qcow2_image(base, target, size):
 
         if not os.path.exists(base):
             prepare_template(target=base, *args, **kwargs)
+        # NOTE(cfb): Having a flavor that sets the root size to 0 and having
+        #            nova effectively ignore that size and use the size of the
+        #            image is considered a feature at this time, not a bug.
+        if size and size < disk.get_disk_size(base):
+            LOG.error('%s virtual size larger than flavor root disk size %s' %
+                      (base, size))
+            raise exception.ImageTooLarge()
         if not os.path.exists(self.path):
             with utils.remove_path_on_error(self.path):
                 copy_qcow2_image(base, self.path, size)