454 lines
14 KiB
Python
454 lines
14 KiB
Python
# Copyright (C) 2011-2014 OpenStack Foundation
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# Copyright (C) 2017 Red Hat
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#
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# Licensed under the Apache License, Version 2.0 (the "License");
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# you may not use this file except in compliance with the License.
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# You may obtain a copy of the License at
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#
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# http://www.apache.org/licenses/LICENSE-2.0
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#
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# Unless required by applicable law or agreed to in writing, software
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# distributed under the License is distributed on an "AS IS" BASIS,
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# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or
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# implied.
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#
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# See the License for the specific language governing permissions and
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# limitations under the License.
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import abc
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import inspect
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import importlib
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import logging
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import os
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import six
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from nodepool import zk
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from nodepool import exceptions
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class Drivers:
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"""The Drivers plugin interface"""
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log = logging.getLogger("nodepool.driver.Drivers")
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drivers = {}
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drivers_paths = None
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@staticmethod
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def _load_class(driver_name, path, parent_class):
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"""Return a driver class that implements the parent_class"""
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spec = importlib.util.spec_from_file_location(driver_name, path)
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module = importlib.util.module_from_spec(spec)
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spec.loader.exec_module(module)
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obj = inspect.getmembers(
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module,
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lambda x: inspect.isclass(x) and issubclass(x, parent_class) and
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x.__module__ == driver_name)
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error = None
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if len(obj) > 1:
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error = "multiple %s implementation" % parent_class
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if not obj:
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error = "no %s implementation found" % parent_class
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if error:
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Drivers.log.error("%s: %s" % (path, error))
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return False
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return obj[0][1]
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@staticmethod
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def load(drivers_paths=[]):
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"""Load drivers"""
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if drivers_paths == Drivers.drivers_paths:
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# Already loaded
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return
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Drivers.drivers.clear()
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for drivers_path in drivers_paths + [os.path.dirname(__file__)]:
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drivers = os.listdir(drivers_path)
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for driver in drivers:
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driver_path = os.path.join(drivers_path, driver)
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if driver in Drivers.drivers:
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Drivers.log.warning("%s: duplicate driver" % driver_path)
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continue
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if not os.path.isdir(driver_path) or \
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"__init__.py" not in os.listdir(driver_path):
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continue
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Drivers.log.debug("%s: loading driver" % driver_path)
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driver_obj = {}
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for name, parent_class in (
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("config", ProviderConfig),
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("handler", NodeRequestHandler),
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("provider", Provider),
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):
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driver_obj[name] = Drivers._load_class(
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driver, os.path.join(driver_path, "%s.py" % name),
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parent_class)
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if not driver_obj[name]:
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break
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if not driver_obj[name]:
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Drivers.log.error("%s: skipping incorrect driver" %
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driver_path)
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continue
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Drivers.drivers[driver] = driver_obj
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Drivers.drivers_paths = drivers_paths
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@staticmethod
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def get(name):
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if not Drivers.drivers:
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Drivers.load()
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try:
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return Drivers.drivers[name]
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except KeyError:
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raise RuntimeError("%s: unknown driver" % name)
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@six.add_metaclass(abc.ABCMeta)
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class Provider(object):
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"""The Provider interface
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The class or instance attribute **name** must be provided as a string.
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"""
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@abc.abstractmethod
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def start(self):
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pass
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@abc.abstractmethod
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def stop(self):
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pass
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@abc.abstractmethod
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def join(self):
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pass
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@abc.abstractmethod
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def labelReady(self, name):
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pass
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@abc.abstractmethod
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def cleanupNode(self, node_id):
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pass
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@abc.abstractmethod
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def waitForNodeCleanup(self, node_id):
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pass
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@abc.abstractmethod
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def cleanupLeakedResources(self):
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pass
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@abc.abstractmethod
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def listNodes(self):
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pass
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@six.add_metaclass(abc.ABCMeta)
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class NodeRequestHandler(object):
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'''
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Class to process a single node request.
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The PoolWorker thread will instantiate a class of this type for each
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node request that it pulls from ZooKeeper.
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Subclasses are required to implement the run_handler method and the
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NodeLaunchManager to kick off any threads needed to satisfy the request.
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'''
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def __init__(self, pw, request):
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'''
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:param PoolWorker pw: The parent PoolWorker object.
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:param NodeRequest request: The request to handle.
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'''
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self.pw = pw
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self.request = request
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self.launch_manager = None
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self.nodeset = []
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self.done = False
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self.paused = False
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self.launcher_id = self.pw.launcher_id
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def _setFromPoolWorker(self):
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'''
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Set values that we pull from the parent PoolWorker.
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We don't do this in __init__ because this class is re-entrant and we
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want the updated values.
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'''
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self.provider = self.pw.getProviderConfig()
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self.pool = self.pw.getPoolConfig()
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self.zk = self.pw.getZK()
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self.manager = self.pw.getProviderManager()
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@property
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def alive_thread_count(self):
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if not self.launch_manager:
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return 0
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return self.launch_manager.alive_thread_count
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# ---------------------------------------------------------------
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# Public methods
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# ---------------------------------------------------------------
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def unlockNodeSet(self, clear_allocation=False):
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'''
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Attempt unlocking all Nodes in the node set.
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:param bool clear_allocation: If true, clears the node allocated_to
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attribute.
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'''
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for node in self.nodeset:
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if not node.lock:
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continue
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if clear_allocation:
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node.allocated_to = None
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self.zk.storeNode(node)
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try:
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self.zk.unlockNode(node)
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except Exception:
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self.log.exception("Error unlocking node:")
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self.log.debug("Unlocked node %s for request %s",
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node.id, self.request.id)
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self.nodeset = []
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def decline_request(self):
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# Technically, this check to see if we've already declined it should
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# not be necessary. But if there is a bug (and there has been), we
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# want to make sure we don't continuously grow this array.
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if self.launcher_id not in self.request.declined_by:
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self.request.declined_by.append(self.launcher_id)
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launchers = set([x.id for x in self.zk.getRegisteredLaunchers()])
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if launchers.issubset(set(self.request.declined_by)):
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# All launchers have declined it
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self.log.debug("Failing declined node request %s",
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self.request.id)
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self.request.state = zk.FAILED
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else:
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self.request.state = zk.REQUESTED
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def run(self):
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'''
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Execute node request handling.
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This code is designed to be re-entrant. Because we can't always
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satisfy a request immediately (due to lack of provider resources), we
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need to be able to call run() repeatedly until the request can be
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fulfilled. The node set is saved and added to between calls.
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'''
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try:
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self.run_handler()
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except Exception:
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self.log.exception(
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"Declining node request %s due to exception in "
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"NodeRequestHandler:", self.request.id)
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self.decline_request()
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self.unlockNodeSet(clear_allocation=True)
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try:
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self.zk.storeNodeRequest(self.request)
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self.zk.unlockNodeRequest(self.request)
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except Exception:
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# If the request is gone for some reason, we need to make
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# sure that self.done still gets set.
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self.log.exception("Unable to decline missing request %s",
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self.request.id)
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self.done = True
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def poll(self):
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'''
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Check if the request has been handled.
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Once the request has been handled, the 'nodeset' attribute will be
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filled with the list of nodes assigned to the request, or it will be
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empty if the request could not be fulfilled.
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:returns: True if we are done with the request, False otherwise.
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'''
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if self.paused:
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return False
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if self.done:
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return True
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if self.launch_manager and not self.launch_manager.poll():
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return False
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# If the request has been pulled, unallocate the node set so other
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# requests can use them.
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if not self.zk.getNodeRequest(self.request.id):
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self.log.info("Node request %s disappeared", self.request.id)
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for node in self.nodeset:
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node.allocated_to = None
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self.zk.storeNode(node)
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self.unlockNodeSet()
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try:
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self.zk.unlockNodeRequest(self.request)
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except exceptions.ZKLockException:
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# If the lock object is invalid that is "ok" since we no
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# longer have a request either. Just do our best, log and
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# move on.
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self.log.debug("Request lock invalid for node request %s "
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"when attempting to clean up the lock",
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self.request.id)
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return True
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if self.launch_manager and self.launch_manager.failed_nodes or \
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len(self.nodeset) != len(self.request.node_types) or \
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[node for node in self.nodeset if node.state != zk.READY]:
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self.log.debug("Declining node request %s because nodes failed",
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self.request.id)
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self.decline_request()
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else:
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# The assigned nodes must be added to the request in the order
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# in which they were requested.
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assigned = []
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for requested_type in self.request.node_types:
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for node in self.nodeset:
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if node.id in assigned:
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continue
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if node.type == requested_type:
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# Record node ID in the request
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self.request.nodes.append(node.id)
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assigned.append(node.id)
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self.log.debug("Fulfilled node request %s",
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self.request.id)
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self.request.state = zk.FULFILLED
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self.unlockNodeSet()
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self.zk.storeNodeRequest(self.request)
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self.zk.unlockNodeRequest(self.request)
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return True
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@abc.abstractmethod
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def run_handler(self):
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pass
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@six.add_metaclass(abc.ABCMeta)
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class NodeLaunchManager(object):
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'''
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Handle launching multiple nodes in parallel.
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Subclasses are required to implement the launch method.
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'''
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def __init__(self, zk, pool, provider_manager,
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requestor, retries):
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'''
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Initialize the launch manager.
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:param ZooKeeper zk: A ZooKeeper object.
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:param ProviderPool pool: A config ProviderPool object.
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:param ProviderManager provider_manager: The manager object used to
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interact with the selected provider.
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:param str requestor: Identifier for the request originator.
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:param int retries: Number of times to retry failed launches.
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'''
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self._retries = retries
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self._nodes = []
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self._failed_nodes = []
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self._ready_nodes = []
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self._threads = []
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self._zk = zk
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self._pool = pool
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self._provider_manager = provider_manager
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self._requestor = requestor
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@property
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def alive_thread_count(self):
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count = 0
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for t in self._threads:
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if t.isAlive():
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count += 1
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return count
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@property
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def failed_nodes(self):
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return self._failed_nodes
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@property
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def ready_nodes(self):
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return self._ready_nodes
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def poll(self):
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'''
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Check if all launch requests have completed.
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When all of the Node objects have reached a final state (READY or
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FAILED), we'll know all threads have finished the launch process.
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'''
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if not self._threads:
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return True
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# Give the NodeLaunch threads time to finish.
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if self.alive_thread_count:
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return False
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node_states = [node.state for node in self._nodes]
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# NOTE: It very important that NodeLauncher always sets one of
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# these states, no matter what.
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if not all(s in (zk.READY, zk.FAILED) for s in node_states):
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return False
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for node in self._nodes:
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if node.state == zk.READY:
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self._ready_nodes.append(node)
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else:
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self._failed_nodes.append(node)
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return True
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@abc.abstractmethod
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def launch(self, node):
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pass
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class ConfigValue(object):
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def __eq__(self, other):
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if isinstance(other, ConfigValue):
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if other.__dict__ == self.__dict__:
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return True
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return False
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def __ne__(self, other):
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return not self.__eq__(other)
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class Driver(ConfigValue):
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pass
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@six.add_metaclass(abc.ABCMeta)
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class ProviderConfig(ConfigValue):
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"""The Provider config interface
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The class or instance attribute **name** must be provided as a string.
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"""
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def __init__(self, provider):
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self.name = provider['name']
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self.provider = provider
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self.driver = Driver()
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self.driver.name = provider.get('driver', 'openstack')
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self.max_concurrency = provider.get('max-concurrency', -1)
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self.driver.manage_images = False
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def __repr__(self):
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return "<Provider %s>" % self.name
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@abc.abstractmethod
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def __eq__(self, other):
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pass
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@abc.abstractmethod
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def reset():
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pass
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@abc.abstractmethod
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def load(self, newconfig):
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pass
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@abc.abstractmethod
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def getSchema(self):
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pass
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