neutron-server啟動過程分析
1. /etc/init.d/neutron-server
DAEMON=/usr/bin/neutron-server DAEMON_ARGS="--log-file=$LOGFILE" DAEMON_DIR=/var/run ... case $1 in start) test "$ENABLED" = "true" || exit 0 log_daemon_msg "Starting neutron server" "neutron-server" start-stop-daemon -Sbmv --pidfile $PIDFILE --chdir $DAEMON_DIR --exec $DAEMON -- $DAEMON_ARGS log_end_msg $? ;; ... esac
2. /usr/bin/neutron-server
import sys from neutron.server import main if __name__ == "__main__": sys.exit(main())
3. neutron.server.main
ef main(): # the configuration will be read into the cfg.CONF global data structure config.init(sys.argv[1:]) if not cfg.CONF.config_file: sys.exit(_("ERROR: Unable to find configuration file via the default" " search paths (~/.neutron/, ~/, /etc/neutron/, /etc/) and" " the '--config-file' option!")) try: pool = eventlet.GreenPool() # 以協程方式啟動Restful API neutron_api = service.serve_wsgi(service.NeutronApiService) api_thread = pool.spawn(neutron_api.wait) # 啟動RPC API try: neutron_rpc = service.serve_rpc() except NotImplementedError: LOG.info(_("RPC was already started in parent process by plugin.")) else: rpc_thread = pool.spawn(neutron_rpc.wait) # api and rpc should die together. When one dies, kill the other. rpc_thread.link(lambda gt: api_thread.kill()) api_thread.link(lambda gt: rpc_thread.kill()) pool.waitall() except KeyboardInterrupt: pass except RuntimeError as e: sys.exit(_("ERROR: %s") % e)
4. 先看neutron.service.serve_rpc()
neutron.service.serve_rpc()最重要的工作就是啟動各個插件的RpcWorker
plugin = manager.NeutronManager.get_plugin() try: rpc = RpcWorker(plugin) if cfg.CONF.rpc_workers < 1: rpc.start() return rpc else: launcher = common_service.ProcessLauncher(wait_interval=1.0) launcher.launch_service(rpc, workers=cfg.CONF.rpc_workers) return launcher
而RpcWorker最重要的工作是調用plugin的start_rpc_listeners來監聽消息隊列:
def start(self): # We may have just forked from parent process. A quick disposal of the # existing sql connections avoids producing errors later when they are # discovered to be broken. session.get_engine().pool.dispose() self._servers = self._plugin.start_rpc_listeners()
5. 再來看Rest API部分
service.serve_wsgi(service.NeutronApiService)
def serve_wsgi(cls): try: service = cls.create() service.start() except Exception: with excutils.save_and_reraise_exception(): LOG.exception(_('Unrecoverable error: please check log ' 'for details.')) return service
service.start()
即為self.wsgi_app = _run_wsgi(self.app_name)
,而該函數最重要的工作是從api-paste.ini中加載app並啟動
def _run_wsgi(app_name): app = config.load_paste_app(app_name) if not app: LOG.error(_('No known API applications configured.')) return server = wsgi.Server("Neutron") server.start(app, cfg.CONF.bind_port, cfg.CONF.bind_host, workers=cfg.CONF.api_workers) # Dump all option values here after all options are parsed cfg.CONF.log_opt_values(LOG, std_logging.DEBUG) LOG.info(_("Neutron service started, listening on %(host)s:%(port)s"), {'host': cfg.CONF.bind_host, 'port': cfg.CONF.bind_port}) return server
6. api-paste.ini
[composite:neutron] use = egg:Paste#urlmap /: neutronversions /v2.0: neutronapi_v2_0 [composite:neutronapi_v2_0] use = call:neutron.auth:pipeline_factory noauth = request_id catch_errors extensions neutronapiapp_v2_0 keystone = request_id catch_errors authtoken keystonecontext extensions neutronapiapp_v2_0 [filter:request_id] paste.filter_factory = neutron.openstack.common.middleware.request_id:RequestIdMiddleware.factory [filter:catch_errors] paste.filter_factory = neutron.openstack.common.middleware.catch_errors:CatchErrorsMiddleware.factory [filter:keystonecontext] paste.filter_factory = neutron.auth:NeutronKeystoneContext.factory [filter:authtoken] paste.filter_factory = keystoneclient.middleware.auth_token:filter_factory [filter:extensions] paste.filter_factory = neutron.api.extensions:plugin_aware_extension_middleware_factory [app:neutronversions] paste.app_factory = neutron.api.versions:Versions.factory [app:neutronapiapp_v2_0] paste.app_factory = neutron.api.v2.router:APIRouter.factory
實例化neutron/api/v2/router.py中的APIRouter
- class APIRouter(wsgi.Router):
- # 一個工廠類方法
- @classmethod
- def factory(cls, global_config, **local_config):
- return cls(**local_config)
- # 真正調用的實例化方法
- def __init__(self, **local_config):
- ...
- #獲取NeutornManage的core_plugin,這個定義在/etc/neutron/neutron.conf,比如我的是
- #core_plugin = neutron.plugins.openvswitch.ovs_neutron_plugin.OVSNeutronPluginV2
- plugin = manager.NeutronManager.get_plugin()
- #掃描特定路徑下的extensions
- ext_mgr = extensions.PluginAwareExtensionManager.get_instance()
- ...
- #定義的局部方法
- def _map_resource(collection, resource, params, parent=None):
- ...
- controller = base.create_resource(
- collection, resource, plugin, params, allow_bulk=allow_bulk,
- parent=parent, allow_pagination=allow_pagination,
- allow_sorting=allow_sorting)
- ...
- # 將這些resource加進router中
- return mapper.collection(collection, resource, **mapper_kwargs)
- # 遍歷 {'network': 'networks', 'subnet': 'subnets','port': 'ports'}
- # 添加controller
- for resource in RESOURCES:
- _map_resource(RESOURCES[resource], resource,
- attributes.RESOURCE_ATTRIBUTE_MAP.get(
- RESOURCES[resource], dict()))
- for resource in SUB_RESOURCES:
- ...
- #其實操作和上面一個差不多,
由這個可以看出,添加的controller類型主要分為三類:(其實只要你在neutron目錄下grep一下,看哪里調用了create_resource
方法即可)
- OVSNeutronPluginV2
- extensions/*.py
- plugins/*.py
針對前兩途徑加載resource的類,下面慢慢進行描述。至於第三種,則是在各個不同的plugin內部額外實現的,不是必須的。
順便簡單的提一下,在neutron/api/extensions.py
下的get_instance
方法,這里其實也是和nova一樣,是遍歷目錄下的py文件,來增加extension的
- ...
- @classmethod
- def get_instance(cls):
- if cls._instance is None:
- cls._instance = cls(get_extensions_path(),
- ... NeutronManager.get_service_plugins())
Resource:OVSNeutronPluginV2的實現
看了代碼的你肯定知道,OVSNeutronPluginV2
這個類,作為core_plugin
繼承了好多的的類
- class OVSNeutronPluginV2(db_base_plugin_v2.NeutronDbPluginV2,
- external_net_db.External_net_db_mixin,
- extraroute_db.ExtraRoute_db_mixin,
- l3_gwmode_db.L3_NAT_db_mixin,
- sg_db_rpc.SecurityGroupServerRpcMixin,
- l3_agentschedulers_db.L3AgentSchedulerDbMixin,
- agentschedulers_db.DhcpAgentSchedulerDbMixin,
- portbindings_db.PortBindingMixin,
- extradhcpopt_db.ExtraDhcpOptMixin,
- addr_pair_db.AllowedAddressPairsMixin):
OVSNeutronPluginV2
基本上沒有什么自己的method,全靠它的"爹們"了。
隨便抓兩個來看下,比如NeutronDbPluginV2
,他的method有get_port
,create_network
之類的,還有L3_NAT_db_mixin
的create_router
等。反正與db的操作,OVSNeutronPluginV2
是不會管的,都在它的父類那邊處理。
再看看OVSNeutronPluginV2
繼承的這些父類們:
- #NeutronDbPluginV2繼承自NeutronPluginBaseV2
- class NeutronDbPluginV2(neutron_plugin_base_v2.NeutronPluginBaseV2,
- CommonDbMixin):
- class NeutronPluginBaseV2(...) :
- @abstractmethod
- def create_subnet(self, context, subnet):
- @abstractmethod
- def update_subnet(self, context, id, subnet):
- @abstractmethod
- def get_subnet(self, context, id, fields=None):
- @abstractmethod
- def get_subnets(self, context, filters=None, fields=None,
其類圖如下:(僅展示部分)
基本上可以說有一個接口類(如圖中的NeutronPluginBaseV2
),定義了抽象方法,然后一個具體的db類來實現(如NeutronDbPluginV2
,這里是采用SQLAlchemy
來完成db模型的)
plugin_aware_extension_middleware_factory
在請求進入APIRouter之前,會先經過RequestIdMiddleware(請求header中添加 openstack.request_id)、CatchErrorsMiddleware(錯誤處理)、keystone權限驗證以及 plugin_aware_extension_middleware_factory等幾個filter的處理,前三個filter比較直 觀,plugin_aware_extension_middleware_factory初始化了Extension目錄下的Resource:
class ExtensionMiddleware(wsgi.Middleware): """Extensions middleware for WSGI.""" def __init__(self, application, ext_mgr=None): self.ext_mgr = (ext_mgr or ExtensionManager(get_extensions_path())) mapper = routes.Mapper() # extended resources ext_mgr.get_resources()其實在內部會調用每個extensions目錄下的extension類的get_resources方法
for resource in self.ext_mgr.get_resources(): path_prefix = resource.path_prefix if resource.parent: path_prefix = (resource.path_prefix + "/%s/{%s_id}" % (resource.parent["collection_name"], resource.parent["member_name"])) LOG.debug(_('Extended resource: %s'), resource.collection) for action, method in resource.collection_actions.iteritems(): conditions = dict(method=[method]) path = "/%s/%s" % (resource.collection, action) with mapper.submapper(controller=resource.controller, action=action, path_prefix=path_prefix, conditions=conditions) as submap: submap.connect(path) submap.connect("%s.:(format)" % path) mapper.resource(resource.collection, resource.collection, controller=resource.controller, member=resource.member_actions, parent_resource=resource.parent, path_prefix=path_prefix) # extended actions action_controllers = self._action_ext_controllers(application, self.ext_mgr, mapper) for action in self.ext_mgr.get_actions(): LOG.debug(_('Extended action: %s'), action.action_name) controller = action_controllers[action.collection] controller.add_action(action.action_name, action.handler) # extended requests req_controllers = self._request_ext_controllers(application, self.ext_mgr, mapper) for request_ext in self.ext_mgr.get_request_extensions(): LOG.debug(_('Extended request: %s'), request_ext.key) controller = req_controllers[request_ext.key] controller.add_handler(request_ext.handler) self._router = routes.middleware.RoutesMiddleware(self._dispatch, mapper) super(ExtensionMiddleware, self).__init__(application)
比如在extensions下的securitygroup
.py中的get_resources
方法,看這個代碼就知道其中可以處理security_group
和security_group_rule
兩類請求了:
@classmethod def get_resources(cls): """Returns Ext Resources.""" my_plurals = [(key, key[:-1]) for key in RESOURCE_ATTRIBUTE_MAP.keys()] attr.PLURALS.update(dict(my_plurals)) exts = [] plugin = manager.NeutronManager.get_plugin() for resource_name in ['security_group', 'security_group_rule']: collection_name = resource_name.replace('_', '-') + "s" params = RESOURCE_ATTRIBUTE_MAP.get(resource_name + "s", dict()) quota.QUOTAS.register_resource_by_name(resource_name) controller = base.create_resource(collection_name, resource_name, plugin, params, allow_bulk=True, allow_pagination=True, allow_sorting=True) ex = extensions.ResourceExtension(collection_name, controller, attr_map=params) exts.append(ex) return exts
如此,Neutron-Server
就已經基本上啟動了,無外乎就是加載配置,router各種resource,然后就等待請求了。其中router哪些resource完全是由配置文件來決定的。 當然,在啟動的過程中也會初始化db,這也就是為何在安裝neutron
的時候無需像nova
,glance
等要執行db sync
的原因了。
參考資料
- Neutron網絡簡介 http://blog.ustack.com/blog/neutron_intro/
- http://www.lnmpy.com/neutron-server-how-to-start/