The reason why the status of volume stuck to "attaching" is that there is error raised from the log of horizon, when I attach the volume to an instance.

[Mon May 28 11:50:50 2012] [error] REQ: curl -i http://9.119.148.119:8776/v1/d3e33bd38cac41aa816925488148494c/volumes/b8a69148-44d5-45
f3-8a07-2a9fd3a8e2e9 -X GET -H "X-Auth-Project-Id: d3e33bd38cac41aa816925488148494c" -H "User-Agent: python-novaclient" -H "Accept: ap
plication/json" -H "X-Auth-Token: 59b2eed030e34e9e9c083a3a24c6bcb8"
[Mon May 28 11:50:50 2012] [error]
[Mon May 28 11:50:50 2012] [error] RESP:{'status': '200', 'content-length': '459', 'content-location': u'http://9.119.148.119:8776/v1/
d3e33bd38cac41aa816925488148494c/volumes/b8a69148-44d5-45f3-8a07-2a9fd3a8e2e9', 'x-compute-request-id': 'req-fe2a96e6-191f-4fc9-bfe0-4
8a1754955a9', 'date': 'Mon, 28 May 2012 03:50:50 GMT', 'content-type': 'application/json'} {"volume": {"status": "in-use", "display_na
me": "vol1", "attachments": [{"device": "/dev/vdc", "server_id": "a5d941a3-b0cb-43ed-b5c9-3f9731f071be", "id": "b8a69148-44d5-45f3-8a0
7-2a9fd3a8e2e9", "volume_id": "b8a69148-44d5-45f3-8a07-2a9fd3a8e2e9"}], "availability_zone": "nova", "created_at": "2012-05-28 03:48:2
6", "display_description": "", "volume_type": "None", "snapshot_id": null, "metadata": {}, "id": "b8a69148-44d5-45f3-8a07-2a9fd3a8e2e9
", "size": 1}}
[Mon May 28 11:50:50 2012] [error]
[Mon May 28 11:50:50 2012] [error] CRITICAL:openstack_dashboard:Unhandled Exception in of type "<type 'exceptions.KeyError'>" in dashb
oard.
[Mon May 28 11:50:50 2012] [error] Traceback (most recent call last):
[Mon May 28 11:50:50 2012] [error]   File "/usr/local/lib/python2.7/dist-packages/django/core/handlers/base.py", line 111, in get_resp
onse
[Mon May 28 11:50:50 2012] [error]     response = callback(request, *callback_args, **callback_kwargs)
[Mon May 28 11:50:50 2012] [error]   File "/opt/stack/horizon/openstack_dashboard/wsgi/../../horizon/decorators.py", line 40, in dec
[Mon May 28 11:50:50 2012] [error]     return view_func(request, *args, **kwargs)
[Mon May 28 11:50:50 2012] [error]   File "/opt/stack/horizon/openstack_dashboard/wsgi/../../horizon/decorators.py", line 55, in dec
[Mon May 28 11:50:50 2012] [error]     return view_func(request, *args, **kwargs)
[Mon May 28 11:50:50 2012] [error]   File "/opt/stack/horizon/openstack_dashboard/wsgi/../../horizon/decorators.py", line 40, in dec
[Mon May 28 11:50:50 2012] [error]     return view_func(request, *args, **kwargs)
[Mon May 28 11:50:50 2012] [error]   File "/usr/local/lib/python2.7/dist-packages/django/views/generic/base.py", line 48, in view
[Mon May 28 11:50:50 2012] [error]     return self.dispatch(request, *args, **kwargs)
[Mon May 28 11:50:50 2012] [error]   File "/usr/local/lib/python2.7/dist-packages/django/views/generic/base.py", line 69, in dispatch
[Mon May 28 11:50:50 2012] [error]     return handler(request, *args, **kwargs)
[Mon May 28 11:50:50 2012] [error]   File "/opt/stack/horizon/openstack_dashboard/wsgi/../../horizon/tables/views.py", line 105, in ge
t
[Mon May 28 11:50:50 2012] [error]     handled = self.construct_tables()
[Mon May 28 11:50:50 2012] [error]   File "/opt/stack/horizon/openstack_dashboard/wsgi/../../horizon/tables/views.py", line 91, in con
struct_tables
[Mon May 28 11:50:50 2012] [error]     preempted = table.maybe_preempt()
[Mon May 28 11:50:50 2012] [error]   File "/opt/stack/horizon/openstack_dashboard/wsgi/../../horizon/tables/base.py", line 982, in may
be_preempt
[Mon May 28 11:50:50 2012] [error]     error = exceptions.handle(request, ignore=True)
[Mon May 28 11:50:50 2012] [error]   File "/opt/stack/horizon/openstack_dashboard/wsgi/../../horizon/tables/base.py", line 978, in may
be_preempt
[Mon May 28 11:50:50 2012] [error]     new_row.load_cells(datum)
[Mon May 28 11:50:50 2012] [error]   File "/opt/stack/horizon/openstack_dashboard/wsgi/../../horizon/tables/base.py", line 365, in loa
d_cells
[Mon May 28 11:50:50 2012] [error]     data = column.get_data(datum)
[Mon May 28 11:50:50 2012] [error]   File "/opt/stack/horizon/openstack_dashboard/wsgi/../../horizon/tables/base.py", line 221, in get
_data
[Mon May 28 11:50:50 2012] [error]     data = self.transform(datum)
[Mon May 28 11:50:50 2012] [error]   File "/opt/stack/horizon/openstack_dashboard/wsgi/../../horizon/dashboards/nova/instances_and_vol
umes/volumes/tables.py", line 96, in get_attachment
[Mon May 28 11:50:50 2012] [error]     "name": attachment["instance"].name,
[Mon May 28 11:50:50 2012] [error] KeyError: 'instance'
[Mon May 28 11:50:50 2012] [error] ERROR:django.request:Internal Server Error: /nova/instances_and_volumes/
[Mon May 28 11:50:50 2012] [error] Traceback (most recent call last):
[Mon May 28 11:50:50 2012] [error]   File "/usr/local/lib/python2.7/dist-packages/django/core/handlers/base.py", line 111, in get_response
[Mon May 28 11:50:50 2012] [error]     response = callback(request, *callback_args, **callback_kwargs)
[Mon May 28 11:50:50 2012] [error]   File "/opt/stack/horizon/openstack_dashboard/wsgi/../../horizon/decorators.py", line 40, in dec
[Mon May 28 11:50:50 2012] [error]     return view_func(request, *args, **kwargs)
[Mon May 28 11:50:50 2012] [error]   File "/opt/stack/horizon/openstack_dashboard/wsgi/../../horizon/decorators.py", line 55, in dec
[Mon May 28 11:50:50 2012] [error]     return view_func(request, *args, **kwargs)
[Mon May 28 11:50:50 2012] [error]   File "/opt/stack/horizon/openstack_dashboard/wsgi/../../horizon/decorators.py", line 40, in dec
[Mon May 28 11:50:50 2012] [error]     return view_func(request, *args, **kwargs)
[Mon May 28 11:50:50 2012] [error]   File "/usr/local/lib/python2.7/dist-packages/django/views/generic/base.py", line 48, in view
[Mon May 28 11:50:50 2012] [error]     return self.dispatch(request, *args, **kwargs)
[Mon May 28 11:50:50 2012] [error]   File "/usr/local/lib/python2.7/dist-packages/django/views/generic/base.py", line 69, in dispatch
[Mon May 28 11:50:50 2012] [error]     return handler(request, *args, **kwargs)
[Mon May 28 11:50:50 2012] [error]   File "/opt/stack/horizon/openstack_dashboard/wsgi/../../horizon/tables/views.py", line 105, in get
[Mon May 28 11:50:50 2012] [error]     handled = self.construct_tables()
[Mon May 28 11:50:50 2012] [error]   File "/opt/stack/horizon/openstack_dashboard/wsgi/../../horizon/tables/views.py", line 91, in construct_tables
[Mon May 28 11:50:50 2012] [error]     preempted = table.maybe_preempt()
[Mon May 28 11:50:50 2012] [error]   File "/opt/stack/horizon/openstack_dashboard/wsgi/../../horizon/tables/base.py", line 982, in maybe_preempt
[Mon May 28 11:50:50 2012] [error]     error = exceptions.handle(request, ignore=True)
[Mon May 28 11:50:50 2012] [error]   File "/opt/stack/horizon/openstack_dashboard/wsgi/../../horizon/tables/base.py", line 978, in maybe_preempt
[Mon May 28 11:50:50 2012] [error]     new_row.load_cells(datum)
[Mon May 28 11:50:50 2012] [error]   File "/opt/stack/horizon/openstack_dashboard/wsgi/../../horizon/tables/base.py", line 365, in load_cells
[Mon May 28 11:50:50 2012] [error]     data = column.get_data(datum)
[Mon May 28 11:50:50 2012] [error]   File "/opt/stack/horizon/openstack_dashboard/wsgi/../../horizon/tables/base.py", line 221, in get_data
[Mon May 28 11:50:50 2012] [error]     data = self.transform(datum)
[Mon May 28 11:50:50 2012] [error]   File "/opt/stack/horizon/openstack_dashboard/wsgi/../../horizon/dashboards/nova/instances_and_volumes/volumes/tables.py", line 96, in get_attachment
[Mon May 28 11:50:50 2012] [error]     "name": attachment["instance"].name,
[Mon May 28 11:50:50 2012] [error] KeyError: 'instance'
[Mon May 28 11:50:50 2012] [error] ERROR:django.request:Internal Server Error: /nova/instances_and_volumes/
[Mon May 28 11:50:50 2012] [error] Traceback (most recent call last):
[Mon May 28 11:50:50 2012] [error]   File "/usr/local/lib/python2.7/dist-packages/django/core/handlers/base.py", line 111, in get_response
[Mon May 28 11:50:50 2012] [error]     response = callback(request, *callback_args, **callback_kwargs)
[Mon May 28 11:50:50 2012] [error]   File "/opt/stack/horizon/openstack_dashboard/wsgi/../../horizon/decorators.py", line 40, in dec
[Mon May 28 11:50:50 2012] [error]     return view_func(request, *args, **kwargs)
[Mon May 28 11:50:50 2012] [error]   File "/opt/stack/horizon/openstack_dashboard/wsgi/../../horizon/decorators.py", line 55, in dec
[Mon May 28 11:50:50 2012] [error]     return view_func(request, *args, **kwargs)
[Mon May 28 11:50:50 2012] [error]   File "/opt/stack/horizon/openstack_dashboard/wsgi/../../horizon/decorators.py", line 40, in dec
[Mon May 28 11:50:50 2012] [error]     return view_func(request, *args, **kwargs)
[Mon May 28 11:50:50 2012] [error]   File "/usr/local/lib/python2.7/dist-packages/django/views/generic/base.py", line 48, in view
[Mon May 28 11:50:50 2012] [error]     return self.dispatch(request, *args, **kwargs)
[Mon May 28 11:50:50 2012] [error]   File "/usr/local/lib/python2.7/dist-packages/django/views/generic/base.py", line 69, in dispatch
[Mon May 28 11:50:50 2012] [error]     return handler(request, *args, **kwargs)
[Mon May 28 11:50:50 2012] [error]   File "/opt/stack/horizon/openstack_dashboard/wsgi/../../horizon/tables/views.py", line 105, in get
[Mon May 28 11:50:50 2012] [error]     handled = self.construct_tables()
[Mon May 28 11:50:50 2012] [error]   File "/opt/stack/horizon/openstack_dashboard/wsgi/../../horizon/tables/views.py", line 91, in construct_tables
[Mon May 28 11:50:50 2012] [error]     preempted = table.maybe_preempt()
[Mon May 28 11:50:50 2012] [error]   File "/opt/stack/horizon/openstack_dashboard/wsgi/../../horizon/tables/base.py", line 982, in maybe_preempt
[Mon May 28 11:50:50 2012] [error]     error = exceptions.handle(request, ignore=True)
[Mon May 28 11:50:50 2012] [error]   File "/opt/stack/horizon/openstack_dashboard/wsgi/../../horizon/tables/base.py", line 978, in maybe_preempt
[Mon May 28 11:50:50 2012] [error]     new_row.load_cells(datum)
[Mon May 28 11:50:50 2012] [error]   File "/opt/stack/horizon/openstack_dashboard/wsgi/../../horizon/tables/base.py", line 365, in load_cells
[Mon May 28 11:50:50 2012] [error]     data = column.get_data(datum)
[Mon May 28 11:50:50 2012] [error]   File "/opt/stack/horizon/openstack_dashboard/wsgi/../../horizon/tables/base.py", line 221, in get_data
[Mon May 28 11:50:50 2012] [error]     data = self.transform(datum)
[Mon May 28 11:50:50 2012] [error]   File "/opt/stack/horizon/openstack_dashboard/wsgi/../../horizon/dashboards/nova/instances_and_volumes/volumes/tables.py", line 96, in get_attachment
[Mon May 28 11:50:50 2012] [error]     "name": attachment["instance"].name,
[Mon May 28 11:50:50 2012] [error] KeyError: 'instance'