关于Cell的基本介绍，可以参考贤哥的一篇文章：
【OpenStack】G版中关于Nova的Cell http://blog.csdn.net/lynn_kong/article/details/8564558
详细的代码分析，可以参考gaoxingnengjisuan的blog：
OpenStack Nova-cell服务的源码解析（编者注：G版）http://blog.csdn.net/gaoxingnengjisuan/article/details/14216977
Cell的服务部署：
Cell的消息路由：
按照官方的推荐部署方案部署：即API Cell只部署nova-api，nova-cells服务，在Child Cell中部署除nova-api之外的全部cell服务（在本人的实际部署中，nova-compute单独部署在另一个节点）
在部署完nova-cells的服务之后，API cell上输入nova-manage service list，输出正常,但只显示本机的nova服务：
Binary Host Zone Status State Updated_At
nova-cells API-cell internal enabled :-) 2014-04-04 09:57:47
在Child Cell 或nova-Compute节点上，输入nova-manage service list，输出也正常，但也只显示本Cell的nova服务：
Binary Host Zone Status State Updated_At
nova-cert Cell internal enabled :-) 2014-04-04 10:00:11
nova-conductor Cell internal enabled :-) 2014-04-04 10:00:19
nova-consoleauth Cell internal enabled :-) 2014-04-04 10:00:12
nova-scheduler Cell internal enabled :-) 2014-04-04 10:00:12
nova-cells Cell internal enabled :-) 2014-04-04 10:00:11
nova-compute Computer3 nova enabled :-) 2014-04-04 10:00:13
但是，在任意节点 终端输入 nova service-list 和 nova host-list 命令将报错：
命令报错：
ERROR: Theserver has either erred or is incapable of performing the requested operation.(HTTP 500) (Request-ID: req-dfa169cf-db9e-44c6-b51b-0d80e4a89e3b)
跟踪 API Cell 节点的 nova-api.log, 输出如下错误信息：
2014-04-04 15:17:25.151 3172 ERROR nova.api.openstack [req-dfa169cf-db9e-44c6-b51b-0d80e4a89e3b 836609a159f244738933dc7c5cb6266a d965a
339b99a4d2da2be18bd0334b9ff] Caught error: invalid literal for int() with base 10: 'api!cell@1'
2014-04-04 15:17:25.151 3172 TRACE nova.api.openstack Traceback (most recent call last):
2014-04-04 15:17:25.151 3172 TRACE nova.api.openstack File "/usr/lib/python2.7/dist-packages/nova/api/openstack/__init__.py", line 1
19, in __call__
2014-04-04 15:17:25.151 3172 TRACE nova.api.openstack return req.get_response(self.application)
2014-04-04 15:17:25.151 3172 TRACE nova.api.openstack File "/usr/lib/python2.7/dist-packages/webob/request.py", line 1296, in send
2014-04-04 15:17:25.151 3172 TRACE nova.api.openstack application, catch_exc_info=False)
2014-04-04 15:17:25.151 3172 TRACE nova.api.openstack File "/usr/lib/python2.7/dist-packages/webob/request.py", line 1260, in call_a
pplication
2014-04-04 15:17:25.151 3172 TRACE nova.api.openstack app_iter = application(self.environ, start_response)
2014-04-04 15:17:25.151 3172 TRACE nova.api.openstack File "/usr/lib/python2.7/dist-packages/webob/dec.py", line 144, in __call__
2014-04-04 15:17:25.151 3172 TRACE nova.api.openstack return resp(environ, start_response)
2014-04-04 15:17:25.151 3172 TRACE nova.api.openstack File "/usr/lib/python2.7/dist-packages/keystoneclient/middleware/auth_token.py
", line 539, in __call__
2014-04-04 15:17:25.151 3172 TRACE nova.api.openstack return self.app(env, start_response) [26/1914]
2014-04-04 15:17:25.151 3172 TRACE nova.api.openstack File "/usr/lib/python2.7/dist-packages/webob/dec.py", line 144, in __call__
2014-04-04 15:17:25.151 3172 TRACE nova.api.openstack return resp(environ, start_response)
2014-04-04 15:17:25.151 3172 TRACE nova.api.openstack File "/usr/lib/python2.7/dist-packages/webob/dec.py", line 144, in __call__
2014-04-04 15:17:25.151 3172 TRACE nova.api.openstack return resp(environ, start_response)
2014-04-04 15:17:25.151 3172 TRACE nova.api.openstack File "/usr/lib/python2.7/dist-packages/routes/middleware.py", line 131, in __c
all__
2014-04-04 15:17:25.151 3172 TRACE nova.api.openstack response = self.app(environ, start_response)
2014-04-04 15:17:25.151 3172 TRACE nova.api.openstack File "/usr/lib/python2.7/dist-packages/webob/dec.py", line 144, in __call__
2014-04-04 15:17:25.151 3172 TRACE nova.api.openstack return resp(environ, start_response)
2014-04-04 15:17:25.151 3172 TRACE nova.api.openstack File "/usr/lib/python2.7/dist-packages/webob/dec.py", line 130, in __call__
2014-04-04 15:17:25.151 3172 TRACE nova.api.openstack resp = self.call_func(req, *args, **self.kwargs)
2014-04-04 15:17:25.151 3172 TRACE nova.api.openstack File "/usr/lib/python2.7/dist-packages/webob/dec.py", line 195, in call_func
2014-04-04 15:17:25.151 3172 TRACE nova.api.openstack return self.func(req, *args, **kwargs)
2014-04-04 15:17:25.151 3172 TRACE nova.api.openstack File "/usr/lib/python2.7/dist-packages/nova/api/openstack/wsgi.py", line 938,
in __call__
2014-04-04 15:17:25.151 3172 TRACE nova.api.openstack content_type, body, accept)
2014-04-04 15:17:25.151 3172 TRACE nova.api.openstack File "/usr/lib/python2.7/dist-packages/nova/api/openstack/wsgi.py", line 997,
in _process_stack
2014-04-04 15:17:25.151 3172 TRACE nova.api.openstack action_result = self.dispatch(meth, request, action_args)
2014-04-04 15:17:25.151 3172 TRACE nova.api.openstack File "/usr/lib/python2.7/dist-packages/nova/api/openstack/wsgi.py", line 1078,
in dispatch
2014-04-04 15:17:25.151 3172 TRACE nova.api.openstack return method(req=request, **action_args)
2014-04-04 15:17:25.151 3172 TRACE nova.api.openstack File "/usr/lib/python2.7/dist-packages/nova/api/openstack/compute/contrib/serv
ices.py", line 139, in index
2014-04-04 15:17:25.151 3172 TRACE nova.api.openstack services = self._get_services_list(req, detailed)
2014-04-04 15:17:25.151 3172 TRACE nova.api.openstack File "/usr/lib/python2.7/dist-packages/nova/api/openstack/compute/contrib/serv
ices.py", line 117, in _get_services_list
2014-04-04 15:17:25.151 3172 TRACE nova.api.openstack services = self._get_services(req)
2014-04-04 15:17:25.151 3172 TRACE nova.api.openstack File "/usr/lib/python2.7/dist-packages/nova/api/openstack/compute/contrib/serv
ices.py", line 86, in _get_services
2014-04-04 15:17:25.151 3172 TRACE nova.api.openstack context, set_zones=True)
2014-04-04 15:17:25.151 3172 TRACE nova.api.openstack File "/usr/lib/python2.7/dist-packages/nova/compute/cells_api.py", line 469, in service_get_all
2014-04-04 15:17:25.151 3172 TRACE nova.api.openstack services)
2014-04-04 15:17:25.151 3172 TRACE nova.api.openstack File "/usr/lib/python2.7/dist-packages/nova/objects/base.py", line 606, in obj
_make_list
2014-04-04 15:17:25.151 3172 TRACE nova.api.openstack **extra_args)
2014-04-04 15:17:25.151 3172 TRACE nova.api.openstack File "/usr/lib/python2.7/dist-packages/nova/objects/service.py", line 67, in _
from_db_object
2014-04-04 15:17:25.151 3172 TRACE nova.api.openstack service[key] = db_service[key]
2014-04-04 15:17:25.151 3172 TRACE nova.api.openstack File "/usr/lib/python2.7/dist-packages/nova/objects/base.py", line 405, in __s
etitem__
2014-04-04 15:17:25.151 3172 TRACE nova.api.openstack setattr(self, name, value)
2014-04-04 15:17:25.151 3172 TRACE nova.api.openstack File "/usr/lib/python2.7/dist-packages/nova/objects/base.py", line 66, in sett
er
2014-04-04 15:17:25.151 3172 TRACE nova.api.openstack return setattr(self, get_attrname(name), typefn(value))
2014-04-04 15:17:25.151 3172 TRACE nova.api.openstack ValueError: invalid literal for int() with base 10: 'api!cell@1'
2014-04-04 15:17:25.151 3172 TRACE nova.api.openstack
2014-04-04 15:17:25.154 3172 INFO nova.api.openstack [req-dfa169cf-db9e-44c6-b51b-0d80e4a89e3b 836609a159f244738933dc7c5cb6266a d965a3
39b99a4d2da2be18bd0334b9ff] http://192.168.122.12:8774/v2/d965a339b99a4d2da2be18bd0334b9ff/os-services returned with HTTP 500
2014-04-04 15:17:25.155 3172 INFO nova.osapi_compute.wsgi.server [req-dfa169cf-db9e-44c6-b51b-0d80e4a89e3b 836609a159f244738933dc7c5cb
6266a d965a339b99a4d2da2be18bd0334b9ff] 192.168.122.14 "GET /v2/d965a339b99a4d2da2be18bd0334b9ff/os-services HTTP/1.1" status: 500 len
: 335 time: 0.1216350
后来查询了N久，发现社区已有人提出Bugs：https://bugs.launchpad.net/nova/+bug/1251043
并已解决：
Reviewed: https://review.openstack.org/81282
Committed: https://git.openstack.org/cgit/openstack/nova/commit/?id=0df94733f7283cbc1e9ae7d27f5cd443158cae8e
因为在Cell中，主机名的ID 前面加了一个前缀：cell routing path，所以格式为<cell routing path>@ID,而nova object模块里，会用一个int()的方法来将id的字符串变为整数，而int('api!cell@1')显然会报一个ValueError！
Patch 中给出的办法就是用一个代理类ServiceProxy，来处理附加在id前面的cell_paths，如下：
class ServiceProxy(object):
def __init__(self, obj, cell_path):
self._obj = obj
self._cell_path = cell_path @property
def id(self):
return cells_utils.cell_with_item(self._cell_path, self._obj.id) def __getitem__(self, key):
if key == 'id':
return self.id return getattr(self._obj, key) def __getattr__(self, key):
return getattr(self._obj, key)
目前，输入nova service-list，得到正常输出，返回各个节点的nova服务，问题解决：
