diff --git a/cinderclient/tests/unit/v1/fakes.py b/cinderclient/tests/unit/v1/fakes.py
index e391dc927..35043d2c1 100644
--- a/cinderclient/tests/unit/v1/fakes.py
+++ b/cinderclient/tests/unit/v1/fakes.py
@@ -330,9 +330,9 @@ class FakeHTTPClient(base_client.HTTPClient):
         assert len(list(body)) == 1
         action = list(body)[0]
         if action == 'os-attach':
-            assert sorted(list(body[action])) == ['instance_uuid',
-                                                  'mode',
-                                                  'mountpoint']
+            keys = sorted(list(body[action]))
+            assert (keys == ['instance_uuid', 'mode', 'mountpoint'] or
+                    keys == ['host_name', 'mode', 'mountpoint'])
         elif action == 'os-detach':
             assert body[action] is None
         elif action == 'os-reserve':
diff --git a/cinderclient/tests/unit/v1/test_volumes.py b/cinderclient/tests/unit/v1/test_volumes.py
index 75c81bd5f..8906a4eba 100644
--- a/cinderclient/tests/unit/v1/test_volumes.py
+++ b/cinderclient/tests/unit/v1/test_volumes.py
@@ -38,6 +38,11 @@ class VolumesTest(utils.TestCase):
         cs.volumes.attach(v, 1, '/dev/vdc', mode='rw')
         cs.assert_called('POST', '/volumes/1234/action')
 
+    def test_attach_to_host(self):
+        v = cs.volumes.get('1234')
+        cs.volumes.attach(v, None, None, host_name='test', mode='rw')
+        cs.assert_called('POST', '/volumes/1234/action')
+
     def test_detach(self):
         v = cs.volumes.get('1234')
         cs.volumes.detach(v)
diff --git a/cinderclient/tests/unit/v2/fakes.py b/cinderclient/tests/unit/v2/fakes.py
index 82cdc9c57..a9e404143 100644
--- a/cinderclient/tests/unit/v2/fakes.py
+++ b/cinderclient/tests/unit/v2/fakes.py
@@ -411,9 +411,9 @@ class FakeHTTPClient(base_client.HTTPClient):
         assert len(list(body)) == 1
         action = list(body)[0]
         if action == 'os-attach':
-            assert sorted(list(body[action])) == ['instance_uuid',
-                                                  'mode',
-                                                  'mountpoint']
+            keys = sorted(list(body[action]))
+            assert (keys == ['instance_uuid', 'mode', 'mountpoint'] or
+                    keys == ['host_name', 'mode', 'mountpoint'])
         elif action == 'os-detach':
             assert body[action] is None
         elif action == 'os-reserve':
diff --git a/cinderclient/tests/unit/v2/test_volumes.py b/cinderclient/tests/unit/v2/test_volumes.py
index d94b47187..8ddb59ed8 100644
--- a/cinderclient/tests/unit/v2/test_volumes.py
+++ b/cinderclient/tests/unit/v2/test_volumes.py
@@ -104,6 +104,11 @@ class VolumesTest(utils.TestCase):
         cs.volumes.attach(v, 1, '/dev/vdc', mode='ro')
         cs.assert_called('POST', '/volumes/1234/action')
 
+    def test_attach_to_host(self):
+        v = cs.volumes.get('1234')
+        cs.volumes.attach(v, None, None, host_name='test', mode='rw')
+        cs.assert_called('POST', '/volumes/1234/action')
+
     def test_detach(self):
         v = cs.volumes.get('1234')
         cs.volumes.detach(v)
diff --git a/cinderclient/v1/volumes.py b/cinderclient/v1/volumes.py
index 3ef3181c2..22cf5aad2 100644
--- a/cinderclient/v1/volumes.py
+++ b/cinderclient/v1/volumes.py
@@ -40,14 +40,17 @@ class Volume(base.Resource):
         """Update the display_name or display_description for this volume."""
         self.manager.update(self, **kwargs)
 
-    def attach(self, instance_uuid, mountpoint, mode='rw'):
+    def attach(self, instance_uuid, mountpoint, mode='rw',
+               host_name=None):
         """Set attachment metadata.
 
         :param instance_uuid: uuid of the attaching instance.
-        :param mountpoint: mountpoint on the attaching instance.
+        :param mountpoint: mountpoint on the attaching instance or host.
         :param mode: the access mode
+        :param host_name: name of the attaching host.
         """
-        return self.manager.attach(self, instance_uuid, mountpoint, mode)
+        return self.manager.attach(self, instance_uuid, mountpoint, mode,
+                                   host_name)
 
     def detach(self):
         """Clear attachment metadata."""
@@ -255,21 +258,24 @@ class VolumeManager(base.ManagerWithFind):
         url = '/volumes/%s/action' % base.getid(volume)
         return self.api.client.post(url, body=body)
 
-    def attach(self, volume, instance_uuid, mountpoint, mode='rw'):
+    def attach(self, volume, instance_uuid, mountpoint, mode='rw',
+               host_name=None):
         """
         Set attachment metadata.
 
         :param volume: The :class:`Volume` (or its ID)
                        you would like to attach.
-        :param instance_uuid: uuid of the attaching instance.
+        :param instance_uuid: uuid of the attaching instance or host.
         :param mountpoint: mountpoint on the attaching instance.
         :param mode: the access mode.
+        :param host_name: name of the attaching host.
         """
-        return self._action('os-attach',
-                            volume,
-                            {'instance_uuid': instance_uuid,
-                             'mountpoint': mountpoint,
-                             'mode': mode})
+        body = {'mountpoint': mountpoint, 'mode': mode}
+        if instance_uuid is not None:
+            body.update({'instance_uuid': instance_uuid})
+        if host_name is not None:
+            body.update({'host_name': host_name})
+        return self._action('os-attach', volume, body)
 
     def detach(self, volume):
         """
diff --git a/cinderclient/v2/volumes.py b/cinderclient/v2/volumes.py
index 28e812954..e2e5368b6 100644
--- a/cinderclient/v2/volumes.py
+++ b/cinderclient/v2/volumes.py
@@ -45,14 +45,16 @@ class Volume(base.Resource):
         """Update the name or description for this volume."""
         self.manager.update(self, **kwargs)
 
-    def attach(self, instance_uuid, mountpoint, mode='rw'):
+    def attach(self, instance_uuid, mountpoint, mode='rw', host_name=None):
         """Set attachment metadata.
 
         :param instance_uuid: uuid of the attaching instance.
-        :param mountpoint: mountpoint on the attaching instance.
+        :param mountpoint: mountpoint on the attaching instance or host.
         :param mode: the access mode.
+        :param host_name: name of the attaching host.
         """
-        return self.manager.attach(self, instance_uuid, mountpoint, mode)
+        return self.manager.attach(self, instance_uuid, mountpoint, mode,
+                                   host_name)
 
     def detach(self):
         """Clear attachment metadata."""
@@ -374,20 +376,23 @@ class VolumeManager(base.ManagerWithFind):
         url = '/volumes/%s/action' % base.getid(volume)
         return self.api.client.post(url, body=body)
 
-    def attach(self, volume, instance_uuid, mountpoint, mode='rw'):
+    def attach(self, volume, instance_uuid, mountpoint, mode='rw',
+               host_name=None):
         """Set attachment metadata.
 
         :param volume: The :class:`Volume` (or its ID)
                        you would like to attach.
         :param instance_uuid: uuid of the attaching instance.
-        :param mountpoint: mountpoint on the attaching instance.
+        :param mountpoint: mountpoint on the attaching instance or host.
         :param mode: the access mode.
+        :param host_name: name of the attaching host.
         """
-        return self._action('os-attach',
-                            volume,
-                            {'instance_uuid': instance_uuid,
-                             'mountpoint': mountpoint,
-                             'mode': mode})
+        body = {'mountpoint': mountpoint, 'mode': mode}
+        if instance_uuid is not None:
+            body.update({'instance_uuid': instance_uuid})
+        if host_name is not None:
+            body.update({'host_name': host_name})
+        return self._action('os-attach', volume, body)
 
     def detach(self, volume):
         """Clear attachment metadata.