diff --git a/nova/objectstore/s3server.py b/nova/objectstore/s3server.py
index a74d76392985..1dc6a264bea5 100644
--- a/nova/objectstore/s3server.py
+++ b/nova/objectstore/s3server.py
@@ -308,6 +308,16 @@ class BucketHandler(BaseRequestHandler):
         self.set_status(204)
         self.finish()
 
+    def head(self, bucket_name):
+        path = os.path.abspath(os.path.join(self.application.directory,
+                                            bucket_name))
+        if (not path.startswith(self.application.directory) or
+                not os.path.isdir(path)):
+            self.set_404()
+            return
+        self.set_status(200)
+        self.finish()
+
 
 class ObjectHandler(BaseRequestHandler):
     def get(self, bucket, object_name):
diff --git a/nova/tests/test_objectstore.py b/nova/tests/test_objectstore.py
index e66bd9fad9f0..3f10cab282ee 100644
--- a/nova/tests/test_objectstore.py
+++ b/nova/tests/test_objectstore.py
@@ -127,10 +127,27 @@ class S3APITestCase(test.NoDBTestCase):
         self._ensure_no_buckets(bucket.get_all_keys())
 
     def test_unknown_bucket(self):
+        # NOTE(unicell): Since Boto v2.25.0, the underlying implementation
+        # of get_bucket method changed from GET to HEAD.
+        #
+        # Prior to v2.25.0, default validate=True fetched a list of keys in the
+        # bucket and raises S3ResponseError. As a side effect of switching to
+        # HEAD request, get_bucket call now generates less error message.
+        #
+        # To keep original semantics, additional get_all_keys call is
+        # suggestted per Boto document. This case tests both validate=False and
+        # validate=True case for completeness.
+        #
+        # http://docs.pythonboto.org/en/latest/releasenotes/v2.25.0.html
+        # http://docs.pythonboto.org/en/latest/s3_tut.html#accessing-a-bucket
         bucket_name = 'falalala'
         self.assertRaises(boto_exception.S3ResponseError,
                           self.conn.get_bucket,
                           bucket_name)
+        bucket = self.conn.get_bucket(bucket_name, validate=False)
+        self.assertRaises(boto_exception.S3ResponseError,
+                          bucket.get_all_keys,
+                          maxkeys=0)
 
     def tearDown(self):
         """Tear down test server."""