trove-taskmanager服务在配置实例，管理实例的生命周期以及对数据库实例执行操作方面做了很多工作。
taskmanager会通过Nova、Swift的API访问Openstack基础的服务，而且是有状态的，是整个系统的核心。
本文通过trove api的代码，来解读taskmanger所具有的功能
from oslo_log import log as logging
import oslo_messaging as messaging
from trove.common import cfg
from trove.common import exception
from trove.common.notification import NotificationCastWrapper
import trove.common.rpc.version as rpc_version
from trove.common.strategies.cluster import strategy
from trove.guestagent import models as agent_models
from trove import rpc
CONF = cfg.CONF
LOG = logging.getLogger(__name__)
class API(object):
"""API for interacting with the task manager."""
def __init__(self, context):
self.context = context
super(API, self).__init__()
target = messaging.Target(topic=CONF.taskmanager_queue,
version=rpc_version.RPC_API_VERSION)
self.version_cap = rpc_version.VERSION_ALIASES.get(
CONF.upgrade_levels.taskmanager)
self.client = self.get_client(target, self.version_cap)
def _cast(self, method_name, version, **kwargs):
LOG.debug("Casting %s" % method_name)
with NotificationCastWrapper(self.context, 'taskmanager'):
cctxt = self.client.prepare(version=version)
cctxt.cast(self.context, method_name, **kwargs)
def get_client(self, target, version_cap, serializer=None):
return rpc.get_client(target,
version_cap=version_cap,
serializer=serializer)
def _transform_obj(self, obj_ref):
# Turn the object into a dictionary and remove the mgr
if "__dict__" in dir(obj_ref): #dir()显示对象的属性 __dict__ : 类的属性（包含一个字典，由类的数据属性组成）
obj_dict = obj_ref.__dict__
# We assume manager contains a object due to the *clients
if obj_dict.get('manager'):
del obj_dict['manager']
return obj_dict
raise ValueError("Could not transform %s" % obj_ref)
def _delete_heartbeat(self, instance_id): #删除心跳
agent_heart_beat = agent_models.AgentHeartBeat()
try:
heartbeat = agent_heart_beat.find_by_instance_id(instance_id)
heartbeat.delete()
except exception.ModelNotFoundError as e:
LOG.error(e.message)
def resize_volume(self, new_size, instance_id): #重新设置卷大小
LOG.debug("Making async call to resize volume for instance: %s"
% instance_id)
self._cast("resize_volume", self.version_cap,
new_size=new_size,
instance_id=instance_id)
def resize_flavor(self, instance_id, old_flavor, new_flavor): #重新设置instance的flavor
LOG.debug("Making async call to resize flavor for instance: %s" %
instance_id)
self._cast("resize_flavor", self.version_cap,
instance_id=instance_id,
old_flavor=self._transform_obj(old_flavor),
new_flavor=self._transform_obj(new_flavor))
def reboot(self, instance_id): #重启（instance）
LOG.debug("Making async call to reboot instance: %s" % instance_id)
self._cast("reboot", self.version_cap, instance_id=instance_id)
def restart(self, instance_id): #重启（数据库）
LOG.debug("Making async call to restart instance: %s" % instance_id)
self._cast("restart", self.version_cap, instance_id=instance_id)
def detach_replica(self, instance_id): #分离副本
LOG.debug("Making async call to detach replica: %s" % instance_id)
self._cast("detach_replica", self.version_cap,
instance_id=instance_id)
def promote_to_replica_source(self, instance_id): #使副本与来源同步
LOG.debug("Making async call to promote replica to source: %s" %
instance_id)
self._cast("promote_to_replica_source", self.version_cap,
instance_id=instance_id)
def eject_replica_source(self, instance_id): #弹出复制源
LOG.debug("Making async call to eject replica source: %s" %
instance_id)
self._cast("eject_replica_source", self.version_cap,
instance_id=instance_id)
def migrate(self, instance_id, host): #迁移
LOG.debug("Making async call to migrate instance: %s" % instance_id)
self._cast("migrate", self.version_cap,
instance_id=instance_id, host=host)
def delete_instance(self, instance_id): #删除instance
LOG.debug("Making async call to delete instance: %s" % instance_id)
self._cast("delete_instance", self.version_cap,
instance_id=instance_id)
def create_backup(self, backup_info, instance_id): #创建备份
LOG.debug("Making async call to create a backup for instance: %s" %
instance_id)
self._cast("create_backup", self.version_cap,
backup_info=backup_info,
instance_id=instance_id)
def delete_backup(self, backup_id): #删除备份
LOG.debug("Making async call to delete backup: %s" % backup_id)
self._cast("delete_backup", self.version_cap, backup_id=backup_id)
def create_instance(self, instance_id, name, flavor, #创建实例
image_id, databases, users, datastore_manager,
packages, volume_size, backup_id=None,
availability_zone=None, root_password=None,
nics=None, overrides=None, slave_of_id=None,
cluster_config=None, volume_type=None,
modules=None, locality=None):
LOG.debug("Making async call to create instance %s " % instance_id)
self._cast("create_instance", self.version_cap,
instance_id=instance_id, name=name,
flavor=self._transform_obj(flavor),
image_id=image_id,
databases=databases,
users=users,
datastore_manager=datastore_manager,
packages=packages,
volume_size=volume_size,
backup_id=backup_id,
availability_zone=availability_zone,
root_password=root_password,
nics=nics,
overrides=overrides,
slave_of_id=slave_of_id,
cluster_config=cluster_config,
volume_type=volume_type,
modules=modules, locality=locality)
def create_cluster(self, cluster_id): #创建集群
LOG.debug("Making async call to create cluster %s " % cluster_id)
self._cast("create_cluster", self.version_cap, cluster_id=cluster_id)
def grow_cluster(self, cluster_id, new_instance_ids): #扩展集群
LOG.debug("Making async call to grow cluster %s " % cluster_id)
cctxt = self.client.prepare(version=self.version_cap)
cctxt.cast(self.context, "grow_cluster",
cluster_id=cluster_id, new_instance_ids=new_instance_ids)
def shrink_cluster(self, cluster_id, instance_ids): #收缩
LOG.debug("Making async call to shrink cluster %s " % cluster_id)
cctxt = self.client.prepare(version=self.version_cap)
cctxt.cast(self.context, "shrink_cluster",
cluster_id=cluster_id, instance_ids=instance_ids)
def delete_cluster(self, cluster_id): #删除集群
LOG.debug("Making async call to delete cluster %s " % cluster_id)
self._cast("delete_cluster", self.version_cap, cluster_id=cluster_id)
def upgrade(self, instance_id, datastore_version_id): #升级数据库版本
LOG.debug("Making async call to upgrade guest to datastore "
"version %s " % datastore_version_id)
cctxt = self.client.prepare(version=self.version_cap)
cctxt.cast(self.context, "upgrade", instance_id=instance_id,
datastore_version_id=datastore_version_id)
def load(context, manager=None):
if manager:
task_manager_api_class = (strategy.load_taskmanager_strategy(manager)
.task_manager_api_class)
else:
task_manager_api_class = API
return task_manager_api_class(context)
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