356 lines
13 KiB
Python
356 lines
13 KiB
Python
# Copyright (c) 2012 Rackspace Hosting
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# All Rights Reserved.
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#
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# Licensed under the Apache License, Version 2.0 (the "License"); you may
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# not use this file except in compliance with the License. You may obtain
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# 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, WITHOUT
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# WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
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# License for the specific language governing permissions and limitations
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# under the License.
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"""
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CellState Manager
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"""
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import copy
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import datetime
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import functools
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from oslo.config import cfg
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from nova.cells import rpc_driver
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from nova import context
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from nova.db import base
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from nova.openstack.common import lockutils
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from nova.openstack.common import log as logging
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from nova.openstack.common import timeutils
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cell_state_manager_opts = [
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cfg.IntOpt('db_check_interval',
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default=60,
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help='Seconds between getting fresh cell info from db.'),
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]
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LOG = logging.getLogger(__name__)
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CONF = cfg.CONF
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CONF.import_opt('name', 'nova.cells.opts', group='cells')
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#CONF.import_opt('capabilities', 'nova.cells.opts', group='cells')
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CONF.register_opts(cell_state_manager_opts, group='cells')
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class CellState(object):
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"""Holds information for a particular cell."""
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def __init__(self, cell_name, is_me=False):
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self.name = cell_name
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self.is_me = is_me
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self.last_seen = datetime.datetime.min
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self.capabilities = {}
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self.capacities = {}
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self.db_info = {}
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# TODO(comstud): The DB will specify the driver to use to talk
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# to this cell, but there's no column for this yet. The only
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# available driver is the rpc driver.
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self.driver = rpc_driver.CellsRPCDriver()
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def update_db_info(self, cell_db_info):
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"""Update cell credentials from db."""
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self.db_info = dict(
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[(k, v) for k, v in cell_db_info.iteritems()
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if k != 'name'])
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def update_capabilities(self, cell_metadata):
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"""Update cell capabilities for a cell."""
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self.last_seen = timeutils.utcnow()
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self.capabilities = cell_metadata
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def update_capacities(self, capacities):
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"""Update capacity information for a cell."""
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self.last_seen = timeutils.utcnow()
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self.capacities = capacities
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def get_cell_info(self):
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"""Return subset of cell information for OS API use."""
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db_fields_to_return = ['is_parent', 'weight_scale', 'weight_offset',
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'username', 'rpc_host', 'rpc_port']
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cell_info = dict(name=self.name, capabilities=self.capabilities)
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if self.db_info:
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for field in db_fields_to_return:
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cell_info[field] = self.db_info[field]
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return cell_info
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def send_message(self, message):
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"""Send a message to a cell. Just forward this to the driver,
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passing ourselves and the message as arguments.
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"""
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self.driver.send_message_to_cell(self, message)
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def __repr__(self):
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me = "me" if self.is_me else "not_me"
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return "Cell '%s' (%s)" % (self.name, me)
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def sync_from_db(f):
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"""Use as a decorator to wrap methods that use cell information to
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make sure they sync the latest information from the DB periodically.
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"""
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@functools.wraps(f)
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def wrapper(self, *args, **kwargs):
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if self._time_to_sync():
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self._cell_db_sync()
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return f(self, *args, **kwargs)
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return wrapper
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class CellStateManager(base.Base):
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def __init__(self, cell_state_cls=None):
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super(CellStateManager, self).__init__()
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if not cell_state_cls:
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cell_state_cls = CellState
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self.cell_state_cls = cell_state_cls
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self.my_cell_state = cell_state_cls(CONF.cells.name, is_me=True)
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self.parent_cells = {}
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self.child_cells = {}
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self.last_cell_db_check = datetime.datetime.min
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self._cell_db_sync()
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my_cell_capabs = {}
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for cap in CONF.cells.capabilities:
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name, value = cap.split('=', 1)
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if ';' in value:
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values = set(value.split(';'))
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else:
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values = set([value])
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my_cell_capabs[name] = values
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self.my_cell_state.update_capabilities(my_cell_capabs)
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def _refresh_cells_from_db(self, ctxt):
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"""Make our cell info map match the db."""
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# Add/update existing cells ...
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db_cells = self.db.cell_get_all(ctxt)
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db_cells_dict = dict([(cell['name'], cell) for cell in db_cells])
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# Update current cells. Delete ones that disappeared
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for cells_dict in (self.parent_cells, self.child_cells):
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for cell_name, cell_info in cells_dict.items():
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is_parent = cell_info.db_info['is_parent']
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db_dict = db_cells_dict.get(cell_name)
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if db_dict and is_parent == db_dict['is_parent']:
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cell_info.update_db_info(db_dict)
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else:
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del cells_dict[cell_name]
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# Add new cells
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for cell_name, db_info in db_cells_dict.items():
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if db_info['is_parent']:
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cells_dict = self.parent_cells
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else:
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cells_dict = self.child_cells
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if cell_name not in cells_dict:
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cells_dict[cell_name] = self.cell_state_cls(cell_name)
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cells_dict[cell_name].update_db_info(db_info)
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def _time_to_sync(self):
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"""Is it time to sync the DB against our memory cache?"""
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diff = timeutils.utcnow() - self.last_cell_db_check
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return diff.seconds >= CONF.cells.db_check_interval
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def _update_our_capacity(self, context):
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"""Update our capacity in the self.my_cell_state CellState.
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This will add/update 2 entries in our CellState.capacities,
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'ram_free' and 'disk_free'.
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The values of these are both dictionaries with the following
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format:
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{'total_mb': <total_memory_free_in_the_cell>,
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'units_by_mb: <units_dictionary>}
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<units_dictionary> contains the number of units that we can
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build for every instance_type that we have. This number is
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computed by looking at room available on every compute_node.
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Take the following instance_types as an example:
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[{'memory_mb': 1024, 'root_gb': 10, 'ephemeral_gb': 100},
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{'memory_mb': 2048, 'root_gb': 20, 'ephemeral_gb': 200}]
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capacities['ram_free']['units_by_mb'] would contain the following:
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{'1024': <number_of_instances_that_will_fit>,
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'2048': <number_of_instances_that_will_fit>}
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capacities['disk_free']['units_by_mb'] would contain the following:
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{'122880': <number_of_instances_that_will_fit>,
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'225280': <number_of_instances_that_will_fit>}
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Units are in MB, so 122880 = (10 + 100) * 1024.
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NOTE(comstud): Perhaps we should only report a single number
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available per instance_type.
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"""
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compute_hosts = {}
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def _get_compute_hosts():
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compute_nodes = self.db.compute_node_get_all(context)
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for compute in compute_nodes:
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service = compute['service']
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if not service or service['disabled']:
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continue
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host = service['host']
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compute_hosts[host] = {
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'free_ram_mb': compute['free_ram_mb'],
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'free_disk_mb': compute['free_disk_gb'] * 1024}
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_get_compute_hosts()
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if not compute_hosts:
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self.my_cell_state.update_capacities({})
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return
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ram_mb_free_units = {}
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disk_mb_free_units = {}
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total_ram_mb_free = 0
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total_disk_mb_free = 0
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def _free_units(tot, per_inst):
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if per_inst:
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return max(0, int(tot / per_inst))
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else:
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return 0
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def _update_from_values(values, instance_type):
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memory_mb = instance_type['memory_mb']
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disk_mb = (instance_type['root_gb'] +
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instance_type['ephemeral_gb']) * 1024
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ram_mb_free_units.setdefault(str(memory_mb), 0)
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disk_mb_free_units.setdefault(str(disk_mb), 0)
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ram_free_units = _free_units(compute_values['free_ram_mb'],
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memory_mb)
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disk_free_units = _free_units(compute_values['free_disk_mb'],
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disk_mb)
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ram_mb_free_units[str(memory_mb)] += ram_free_units
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disk_mb_free_units[str(disk_mb)] += disk_free_units
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instance_types = self.db.instance_type_get_all(context)
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for compute_values in compute_hosts.values():
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total_ram_mb_free += compute_values['free_ram_mb']
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total_disk_mb_free += compute_values['free_disk_mb']
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for instance_type in instance_types:
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_update_from_values(compute_values, instance_type)
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capacities = {'ram_free': {'total_mb': total_ram_mb_free,
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'units_by_mb': ram_mb_free_units},
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'disk_free': {'total_mb': total_disk_mb_free,
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'units_by_mb': disk_mb_free_units}}
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self.my_cell_state.update_capacities(capacities)
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@lockutils.synchronized('cell-db-sync', 'nova-')
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def _cell_db_sync(self):
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"""Update status for all cells if it's time. Most calls to
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this are from the check_for_update() decorator that checks
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the time, but it checks outside of a lock. The duplicate
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check here is to prevent multiple threads from pulling the
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information simultaneously.
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"""
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if self._time_to_sync():
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LOG.debug(_("Updating cell cache from db."))
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self.last_cell_db_check = timeutils.utcnow()
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ctxt = context.get_admin_context()
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self._refresh_cells_from_db(ctxt)
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self._update_our_capacity(ctxt)
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@sync_from_db
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def get_cell_info_for_neighbors(self):
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"""Return cell information for all neighbor cells."""
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cell_list = [cell.get_cell_info()
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for cell in self.child_cells.itervalues()]
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cell_list.extend([cell.get_cell_info()
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for cell in self.parent_cells.itervalues()])
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return cell_list
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@sync_from_db
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def get_my_state(self):
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"""Return information for my (this) cell."""
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return self.my_cell_state
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@sync_from_db
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def get_child_cells(self):
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"""Return list of child cell_infos."""
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return self.child_cells.values()
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@sync_from_db
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def get_parent_cells(self):
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"""Return list of parent cell_infos."""
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return self.parent_cells.values()
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@sync_from_db
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def get_parent_cell(self, cell_name):
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return self.parent_cells.get(cell_name)
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@sync_from_db
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def get_child_cell(self, cell_name):
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return self.child_cells.get(cell_name)
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@sync_from_db
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def update_cell_capabilities(self, cell_name, capabilities):
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"""Update capabilities for a cell."""
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cell = self.child_cells.get(cell_name)
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if not cell:
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cell = self.parent_cells.get(cell_name)
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if not cell:
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LOG.error(_("Unknown cell '%(cell_name)s' when trying to "
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"update capabilities"), locals())
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return
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# Make sure capabilities are sets.
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for capab_name, values in capabilities.items():
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capabilities[capab_name] = set(values)
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cell.update_capabilities(capabilities)
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@sync_from_db
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def update_cell_capacities(self, cell_name, capacities):
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"""Update capacities for a cell."""
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cell = self.child_cells.get(cell_name)
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if not cell:
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cell = self.parent_cells.get(cell_name)
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if not cell:
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LOG.error(_("Unknown cell '%(cell_name)s' when trying to "
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"update capacities"), locals())
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return
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cell.update_capacities(capacities)
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@sync_from_db
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def get_our_capabilities(self, include_children=True):
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capabs = copy.deepcopy(self.my_cell_state.capabilities)
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if include_children:
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for cell in self.child_cells.values():
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for capab_name, values in cell.capabilities.items():
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if capab_name not in capabs:
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capabs[capab_name] = set([])
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capabs[capab_name] |= values
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return capabs
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def _add_to_dict(self, target, src):
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for key, value in src.items():
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if isinstance(value, dict):
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target.setdefault(key, {})
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self._add_to_dict(target[key], value)
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continue
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target.setdefault(key, 0)
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target[key] += value
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@sync_from_db
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def get_our_capacities(self, include_children=True):
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capacities = copy.deepcopy(self.my_cell_state.capacities)
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if include_children:
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for cell in self.child_cells.values():
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self._add_to_dict(capacities, cell.capacities)
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return capacities
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