1. 各个组件之间可以互相调用（都是common sense）
conductor 负责DB的操作。
各个组件之间通过RPC， 序列化通过oslo_versionedobjects。
2. 具体调用：
Agent（如nova-computer） 访问DB， 通过调用conductor。 实例， 搜索remotable_classmethod
这个调用比较隐性， 通过versionedobjects （ppt）的remote方法。
# These are decorators that mark an object's method as remotable. # If the metaclass is configured to forward object methods to an # indirection service, these will result in making an RPC call # instead of directly calling the implementation in the object. Instead, # the object implementation on the remote end will perform the # requested action and the result will be returned here. def remotable_classmethod(fn): """Decorator for remotable classmethods.""" @six.wraps(fn) def wrapper(cls, context, *args, **kwargs): if cls.indirection_api: version_manifest = obj_tree_get_versions(cls.obj_name()) try: # 需要设置indirection_api， 还需要提供 object_class_action_versions方法 result = cls.indirection_api.object_class_action_versions( context, cls.obj_name(), fn.__name__, version_manifest, args, kwargs) except NotImplementedError: # FIXME(danms): Maybe start to warn here about deprecation? result = cls.indirection_api.object_class_action( context, cls.obj_name(), fn.__name__, cls.VERSION, args, kwargs) else: result = fn(cls, context, *args, **kwargs) if isinstance(result, VersionedObject): result._context = context return result # NOTE(danms): Make this discoverable wrapper.remotable = True wrapper.original_fn = fn return classmethod(wrapper)
# See comment above for remotable_classmethod() # # Note that this will use either the provided context, or the one # stashed in the object. If neither are present, the object is # "orphaned" and remotable methods cannot be called. def remotable(fn): """Decorator for remotable object methods.""" @six.wraps(fn) def wrapper(self, *args, **kwargs): ctxt = self._context if ctxt is None: raise exception.OrphanedObjectError(method=fn.__name__, objtype=self.obj_name()) if self.indirection_api: # 需要设置indirection_api 及其 object_action 方法 updates, result = self.indirection_api.object_action( ctxt, self, fn.__name__, args, kwargs) for key, value in updates.items(): if key in self.fields: field = self.fields[key] # NOTE(ndipanov): Since VersionedObjectSerializer will have # deserialized any object fields into objects already, # we do not try to deserialize them again here. if isinstance(value, VersionedObject): setattr(self, key, value) else: setattr(self, key, field.from_primitive(self, key, value)) self.obj_reset_changes() self._changed_fields = set(updates.get('obj_what_changed', [])) return result else: return fn(self, *args, **kwargs) wrapper.remotable = True wrapper.original_fn = fn return wrapper
3. Agent调用conductor。
objects_base.NovaObject.indirection_api = conductor_rpcapi.ConductorAPI()
def main(): config.parse_args(sys.argv) logging.setup(CONF, 'nova') priv_context.init(root_helper=shlex.split(utils.get_root_helper())) utils.monkey_patch() objects.register_all() gmr_opts.set_defaults(CONF) # Ensure os-vif objects are registered and plugins loaded os_vif.initialize() gmr.TextGuruMeditation.setup_autorun(version, conf=CONF) cmd_common.block_db_access('nova-compute') objects_base.NovaObject.indirection_api = conductor_rpcapi.ConductorAPI() objects.Service.enable_min_version_cache() server = service.Service.create(binary='nova-compute', topic=compute_rpcapi.RPC_TOPIC) service.serve(server) service.wait()
4. API调用 其他组件
调用agent（nova-compute）：
class ServersController(wsgi.Controller) 的初始化 def __init__(self, **kwargs)
self.compute_api = compute.API()
from nova import compute class ServersController(wsgi.Controller): """The Server API base controller class for the OpenStack API.""" _view_builder_class = views_servers.ViewBuilder ...... def __init__(self, **kwargs): super(ServersController, self).__init__(**kwargs) self.compute_api = compute.API()
5. nova objects隐性的调用conductor
class NovaObjectSerializer(messaging.NoOpSerializer): """A NovaObject-aware Serializer. This implements the Oslo Serializer interface and provides the ability to serialize and deserialize NovaObject entities. Any service that needs to accept or return NovaObjects as arguments or result values should pass this to its RPCClient and RPCServer objects. """ @property def conductor(self): if not hasattr(self, '_conductor'): from nova import conductor self._conductor = conductor.API() return self._conductor
class CyborgObjectSerializer 没有实现。
5. nova 其他地方调用conductor
$ git grep "from.*conductor" cells/scheduler.py:from nova import conductor cmd/api_metadata.py:from nova.conductor import rpcapi as conductor_rpcapi cmd/compute.py:from nova.conductor import rpcapi as conductor_rpcapi cells/scheduler.py:from nova import conductor cmd/api_metadata.py:from nova.conductor import rpcapi as conductor_rpcapi cmd/compute.py:from nova.conductor import rpcapi as conductor_rpcapi cmd/dhcpbridge.py:from nova.conductor import rpcapi as conductor_rpcapi cells/scheduler.py:from nova import conductor cmd/api_metadata.py:from nova.conductor import rpcapi as conductor_rpcapi cmd/compute.py:from nova.conductor import rpcapi as conductor_rpcapi cmd/dhcpbridge.py:from nova.conductor import rpcapi as conductor_rpcapi cmd/network.py:from nova.conductor import rpcapi as conductor_rpcapi compute/api.py:from nova import conductor compute/api.py: # from the conductor LiveMigrationTask. Yes this is tightly-coupled compute/manager.py:from nova import conductor compute/manager.py: This is initiated from conductor and runs on the destination host. conductor/__init__.py:from nova.conductor import api as conductor_api conductor/api.py:from nova.conductor import rpcapi conductor/manager.py:from nova.conductor.tasks import live_migrate conductor/manager.py:from nova.conductor.tasks import migrate conductor/manager.py: # can't reach the API DB from the cell conductor. conductor/tasks/live_migrate.py:from nova.conductor.tasks import base conductor/tasks/live_migrate.py:from nova.conductor.tasks import migrate conductor/tasks/migrate.py:from nova.conductor.tasks import base conf/__init__.py:from nova.conf import conductor objects/base.py: from nova import conductor service.py:from nova import conductor
service.py 调用 conductor
from nova import conductor ...... class Service(service.Service): """Service object for binaries running on hosts. A service takes a manager and enables rpc by listening to queues based on topic. It also periodically runs tasks on the manager and reports its state to the database services table. """ def __init__(self, host, binary, topic, manager, report_interval=None, periodic_enable=None, periodic_fuzzy_delay=None, periodic_interval_max=None, *args, **kwargs): super(Service, self).__init__() self.host = host self.binary = binary self.topic = topic self.manager_class_name = manager self.servicegroup_api = servicegroup.API() manager_class = importutils.import_class(self.manager_class_name) self.manager = manager_class(host=self.host, *args, **kwargs) self.rpcserver = None self.report_interval = report_interval self.periodic_enable = periodic_enable self.periodic_fuzzy_delay = periodic_fuzzy_delay self.periodic_interval_max = periodic_interval_max self.saved_args, self.saved_kwargs = args, kwargs self.backdoor_port = None if objects_base.NovaObject.indirection_api: conductor_api = conductor.API() conductor_api.wait_until_ready(context.get_admin_context()) setup_profiler(binary, self.host)
6. conductor 调用了 agent（nova-computer）
$ cd conductor/ ; git grep "from.*compute" -bash: cd: conductor/: No such file or directory manager.py:from nova.compute import instance_actions manager.py:from nova.compute import rpcapi as compute_rpcapi manager.py:from nova.compute import task_states manager.py:from nova.compute import utils as compute_utils manager.py:from nova.compute.utils import wrap_instance_event manager.py:from nova.compute import vm_states manager.py: # or during a reschedule from a pre-Queens compute. In all other cases, manager.py: # could have come from a compute via reschedule and it would tasks/live_migrate.py:from nova.compute import power_state