OpenStack Block Storage (Cinder)
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# Copyright (c) 2011 OpenStack Foundation
# All Rights Reserved.
# Licensed under the Apache License, Version 2.0 (the "License"); you may
# not use this file except in compliance with the License. You may obtain
# a copy of the License at
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
# WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
# License for the specific language governing permissions and limitations
# under the License.
"""Manage backends in the current zone."""
from collections import abc
import random
from oslo_config import cfg
from oslo_log import log as logging
from oslo_utils import importutils
from oslo_utils import strutils
from oslo_utils import timeutils
from cinder.common import constants
from cinder import context as cinder_context
from cinder import exception
from cinder import objects
from cinder.scheduler import filters
from cinder import utils
from cinder.volume import volume_types
from cinder.volume import volume_utils
# FIXME: This file should be renamed to backend_manager, we should also rename
# HostManager class, and scheduler_host_manager option, and also the weight
# classes, and add code to maintain backward compatibility.
host_manager_opts = [
help='Which filter class names to use for filtering hosts '
'when not specified in the request.'),
help='Which weigher class names to use for weighing hosts.'),
help='Which handler to use for selecting the host/pool '
'after weighing'),
CONF.import_opt('scheduler_driver', 'cinder.scheduler.manager')
CONF.import_opt('max_over_subscription_ratio', 'cinder.volume.driver')
LOG = logging.getLogger(__name__)
class ReadOnlyDict(abc.Mapping):
"""A read-only dict."""
def __init__(self, source=None):
if source is not None: = dict(source)
else: = {}
def __getitem__(self, key):
def __iter__(self):
return iter(
def __len__(self):
return len(
def __repr__(self):
return '%s(%r)' % (self.__class__.__name__,
class BackendState(object):
"""Mutable and immutable information tracked for a volume backend."""
def __init__(self, host, cluster_name, capabilities=None, service=None):
# NOTE(geguileo): We have a circular dependency between BackendState
# and PoolState and we resolve it with an instance attribute instead
# of a class attribute that we would assign after the PoolState
# declaration because this way we avoid splitting the code.
self.pool_state_cls = PoolState
self.capabilities = None
self.service = None = host
self.cluster_name = cluster_name
self.update_capabilities(capabilities, service)
self.volume_backend_name = None
self.vendor_name = None
self.driver_version = 0
self.storage_protocol = None
self.QoS_support = False
# Mutable available resources.
# These will change as resources are virtually "consumed".
self.total_capacity_gb = 0
# capacity has been allocated in cinder POV, which should be
# sum(vol['size'] for vol in vols_on_hosts)
self.allocated_capacity_gb = 0
self.free_capacity_gb = None
self.reserved_percentage = 0
# The apparent allocated space indicating how much capacity
# has been provisioned. This could be the sum of sizes of
# all volumes on a backend, which could be greater than or
# equal to the allocated_capacity_gb.
self.provisioned_capacity_gb = 0
self.max_over_subscription_ratio = 1.0
self.thin_provisioning_support = False
self.thick_provisioning_support = False
# Does this backend support attaching a volume to more than
# one host/instance?
self.multiattach = False
self.filter_function = None
self.goodness_function = 0
# PoolState for all pools
self.pools = {}
self.updated = None
def backend_id(self):
return self.cluster_name or
def update_capabilities(self, capabilities=None, service=None):
# Read-only capability dicts
if capabilities is None:
capabilities = {}
self.capabilities = ReadOnlyDict(capabilities)
if service is None:
service = {}
self.service = ReadOnlyDict(service)
def update_from_volume_capability(self, capability, service=None):
"""Update information about a host from its volume_node info.
'capability' is the status info reported by volume backend, a typical
capability looks like this:
.. code-block:: python
capability = {
'volume_backend_name': 'Local iSCSI', #
'vendor_name': 'OpenStack', # backend level
'driver_version': '1.0', # mandatory/fixed
'storage_protocol': 'iSCSI', # stats&capabilities
'active_volumes': 10, #
'IOPS_provisioned': 30000, # optional custom
'fancy_capability_1': 'eat', # stats & capabilities
'fancy_capability_2': 'drink', #
'pools': [
{'pool_name': '1st pool', #
'total_capacity_gb': 500, # mandatory stats for
'free_capacity_gb': 230, # pools
'allocated_capacity_gb': 270, #
'QoS_support': 'False', #
'reserved_percentage': 0, #
'dying_disks': 100, #
'super_hero_1': 'spider-man', # optional custom
'super_hero_2': 'flash', # stats & capabilities
'super_hero_3': 'neoncat' #
{'pool_name': '2nd pool',
'total_capacity_gb': 1024,
'free_capacity_gb': 1024,
'allocated_capacity_gb': 0,
'QoS_support': 'False',
'reserved_percentage': 0,
'dying_disks': 200,
'super_hero_1': 'superman',
'super_hero_2': ' ',
'super_hero_2': 'Hulk'
self.update_capabilities(capability, service)
if capability:
if self.updated and self.updated > capability['timestamp']:
# Update backend level info
# Update pool level info
self.update_pools(capability, service)
def update_pools(self, capability, service):
"""Update storage pools information from backend reported info."""
if not capability:
pools = capability.get('pools', None)
active_pools = set()
if pools and isinstance(pools, list):
# Update all pools stats according to information from list
# of pools in volume capacity
for pool_cap in pools:
pool_name = pool_cap['pool_name']
cur_pool = self.pools.get(pool_name, None)
if not cur_pool:
# Add new pool
cur_pool = self.pool_state_cls(,
self.pools[pool_name] = cur_pool
cur_pool.update_from_volume_capability(pool_cap, service)
elif pools is None:
# To handle legacy driver that doesn't report pool
# information in the capability, we have to prepare
# a pool from backend level info, or to update the one
# we created in self.pools.
pool_name = self.volume_backend_name
if pool_name is None:
pool_name = volume_utils.extract_host(, 'pool', True)
if len(self.pools) == 0:
# No pool was there
single_pool = self.pool_state_cls(, self.cluster_name,
capability, pool_name)
self.pools[pool_name] = single_pool
# this is an update from legacy driver
single_pool = self.pools[pool_name]
except KeyError:
single_pool = self.pool_state_cls(,
self.pools[pool_name] = single_pool
single_pool.update_from_volume_capability(capability, service)
# remove non-active pools from self.pools
nonactive_pools = set(self.pools.keys()) - active_pools
for pool in nonactive_pools:
LOG.debug("Removing non-active pool %(pool)s @ %(host)s "
"from scheduler cache.", {'pool': pool,
del self.pools[pool]
def _append_backend_info(self, pool_cap):
# Fill backend level info to pool if needed.
if not pool_cap.get('volume_backend_name', None):
pool_cap['volume_backend_name'] = self.volume_backend_name
if not pool_cap.get('storage_protocol', None):
pool_cap['storage_protocol'] = self.storage_protocol
if not pool_cap.get('vendor_name', None):
pool_cap['vendor_name'] = self.vendor_name
if not pool_cap.get('driver_version', None):
pool_cap['driver_version'] = self.driver_version
if not pool_cap.get('timestamp', None):
pool_cap['timestamp'] = self.updated
if('filter_function' not in pool_cap and
'filter_function' in self.capabilities):
pool_cap['filter_function'] = self.capabilities['filter_function']
if('goodness_function' not in pool_cap and
'goodness_function' in self.capabilities):
pool_cap['goodness_function'] = (
def update_backend(self, capability):
self.volume_backend_name = capability.get('volume_backend_name', None)
self.vendor_name = capability.get('vendor_name', None)
self.driver_version = capability.get('driver_version', None)
self.storage_protocol = capability.get('storage_protocol', None)
self.updated = capability['timestamp']
def consume_from_volume(self, volume, update_time=True):
"""Incrementally update host state from a volume."""
volume_gb = volume['size']
self.allocated_capacity_gb += volume_gb
self.provisioned_capacity_gb += volume_gb
if self.free_capacity_gb == 'infinite':
# There's virtually infinite space on back-end
elif self.free_capacity_gb == 'unknown':
# Unable to determine the actual free space on back-end
self.free_capacity_gb -= volume_gb
if update_time:
self.updated = timeutils.utcnow()
LOG.debug("Consumed %s GB from backend: %s", volume['size'], self)
def __repr__(self):
# FIXME(zhiteng) backend level free_capacity_gb isn't as
# meaningful as it used to be before pool is introduced, we'd
# come up with better representation of HostState.
grouping = 'cluster' if self.cluster_name else 'host'
grouping_name = self.backend_id
return ("%(grouping)s '%(grouping_name)s':"
"free_capacity_gb: %(free_capacity_gb)s, "
"total_capacity_gb: %(total_capacity_gb)s,"
"allocated_capacity_gb: %(allocated_capacity_gb)s, "
"max_over_subscription_ratio: %(mosr)s,"
"reserved_percentage: %(reserved_percentage)s, "
"provisioned_capacity_gb: %(provisioned_capacity_gb)s,"
"thin_provisioning_support: %(thin_provisioning_support)s, "
"thick_provisioning_support: %(thick)s,"
"pools: %(pools)s,"
"updated at: %(updated)s" %
{'grouping': grouping, 'grouping_name': grouping_name,
'free_capacity_gb': self.free_capacity_gb,
'total_capacity_gb': self.total_capacity_gb,
'allocated_capacity_gb': self.allocated_capacity_gb,
'mosr': self.max_over_subscription_ratio,
'reserved_percentage': self.reserved_percentage,
'provisioned_capacity_gb': self.provisioned_capacity_gb,
'thin_provisioning_support': self.thin_provisioning_support,
'thick': self.thick_provisioning_support,
'pools': self.pools, 'updated': self.updated})
class PoolState(BackendState):
def __init__(self, host, cluster_name, capabilities, pool_name):
new_host = volume_utils.append_host(host, pool_name)
new_cluster = volume_utils.append_host(cluster_name, pool_name)
super(PoolState, self).__init__(new_host, new_cluster, capabilities)
self.pool_name = pool_name
# No pools in pool
self.pools = None
def update_from_volume_capability(self, capability, service=None):
"""Update information about a pool from its volume_node info."""
LOG.debug("Updating capabilities for %s: %s",, capability)
self.update_capabilities(capability, service)
if capability:
if self.updated and self.updated > capability['timestamp']:
self.total_capacity_gb = capability.get('total_capacity_gb', 0)
self.free_capacity_gb = capability.get('free_capacity_gb', 0)
self.allocated_capacity_gb = capability.get(
'allocated_capacity_gb', 0)
self.QoS_support = capability.get('QoS_support', False)
self.reserved_percentage = capability.get('reserved_percentage', 0)
# provisioned_capacity_gb is the apparent total capacity of
# all the volumes created on a backend, which is greater than
# or equal to allocated_capacity_gb, which is the apparent
# total capacity of all the volumes created on a backend
# in Cinder. Using allocated_capacity_gb as the default of
# provisioned_capacity_gb if it is not set.
self.provisioned_capacity_gb = capability.get(
'provisioned_capacity_gb', self.allocated_capacity_gb)
self.thin_provisioning_support = capability.get(
'thin_provisioning_support', False)
self.thick_provisioning_support = capability.get(
'thick_provisioning_support', False)
self.max_over_subscription_ratio = (
capability, CONF.max_over_subscription_ratio))
self.multiattach = capability.get('multiattach', False)
self.filter_function = capability.get('filter_function', None)
self.goodness_function = capability.get('goodness_function', 0)
def update_pools(self, capability):
# Do nothing, since we don't have pools within pool, yet
class HostManager(object):
"""Base HostManager class."""
backend_state_cls = BackendState
ALLOWED_SERVICE_NAMES = ('volume', 'backup')
REQUIRED_KEYS = frozenset([
def __init__(self):
self.service_states = {} # { <host|cluster>: {<service>: {cap k : v}}}
self.backend_state_map = {}
self.backup_service_states = {}
self.filter_handler = filters.BackendFilterHandler('cinder.scheduler.'
self.filter_classes = self.filter_handler.get_all_classes()
self.enabled_filters = self._choose_backend_filters(
self.weight_handler = importutils.import_object(
self.weight_classes = self.weight_handler.get_all_classes()
self._no_capabilities_backends = set() # Services without capabilities
self.service_states_last_update = {}
def _choose_backend_filters(self, filter_cls_names):
"""Return a list of available filter names.
This function checks input filter names against a predefined set
of acceptable filters (all loaded filters). If input is None,
it uses CONF.scheduler_default_filters instead.
if not isinstance(filter_cls_names, (list, tuple)):
filter_cls_names = [filter_cls_names]
good_filters = []
bad_filters = []
for filter_name in filter_cls_names:
found_class = False
for cls in self.filter_classes:
if cls.__name__ == filter_name:
found_class = True
if not found_class:
if bad_filters:
raise exception.SchedulerHostFilterNotFound(
filter_name=", ".join(bad_filters))
return good_filters
def _choose_backend_weighers(self, weight_cls_names):
"""Return a list of available weigher names.
This function checks input weigher names against a predefined set
of acceptable weighers (all loaded weighers). If input is None,
it uses CONF.scheduler_default_weighers instead.
if weight_cls_names is None:
weight_cls_names = CONF.scheduler_default_weighers
if not isinstance(weight_cls_names, (list, tuple)):
weight_cls_names = [weight_cls_names]
good_weighers = []
bad_weighers = []
for weigher_name in weight_cls_names:
found_class = False
for cls in self.weight_classes:
if cls.__name__ == weigher_name:
found_class = True
if not found_class:
if bad_weighers:
raise exception.SchedulerHostWeigherNotFound(
weigher_name=", ".join(bad_weighers))
return good_weighers
def get_filtered_backends(self, backends, filter_properties,
"""Filter backends and return only ones passing all filters."""
if filter_class_names is not None:
filter_classes = self._choose_backend_filters(filter_class_names)
filter_classes = self.enabled_filters
return self.filter_handler.get_filtered_objects(filter_classes,
def get_weighed_backends(self, backends, weight_properties,
"""Weigh the backends."""
weigher_classes = self._choose_backend_weighers(weigher_class_names)
weighed_backends = self.weight_handler.get_weighed_objects(
weigher_classes, backends, weight_properties)
LOG.debug("Weighed %s", weighed_backends)
return weighed_backends
def update_service_capabilities(self, service_name, host, capabilities,
cluster_name, timestamp):
"""Update the per-service capabilities based on this notification."""
if service_name not in HostManager.ALLOWED_SERVICE_NAMES:
LOG.debug('Ignoring %(service_name)s service update '
'from %(host)s',
{'service_name': service_name, 'host': host})
# Determine whether HostManager has just completed initialization, and
# has not received the rpc message returned by volume.
just_init = self._is_just_initialized()
# TODO(geguileo): In P - Remove the next line since we receive the
# timestamp
timestamp = timestamp or timeutils.utcnow()
# Copy the capabilities, so we don't modify the original dict
capab_copy = dict(capabilities)
capab_copy["timestamp"] = timestamp
# Set the default capabilities in case None is set.
backend = cluster_name or host
if service_name == 'backup':
self.backup_service_states[backend] = capabilities
LOG.debug("Received %(service_name)s service update from "
"%(host)s: %(cap)s",
{'service_name': service_name, 'host': host,
'cap': capabilities})
capab_old = self.service_states.get(backend, {"timestamp": 0})
capab_last_update = self.service_states_last_update.get(
backend, {"timestamp": 0})
# Ignore older updates
if capab_old['timestamp'] and timestamp < capab_old['timestamp']:'Ignoring old capability report from %s.', backend)
# If the capabilities are not changed and the timestamp is older,
# record the capabilities.
# There are cases: capab_old has the capabilities set,
# but the timestamp may be None in it. So does capab_last_update.
if (not self._get_updated_pools(capab_old, capab_copy)) and (
(not capab_old.get("timestamp")) or
(not capab_last_update.get("timestamp")) or
(capab_last_update["timestamp"] < capab_old["timestamp"])):
self.service_states_last_update[backend] = capab_old
self.service_states[backend] = capab_copy
cluster_msg = (('Cluster: %s - Host: ' % cluster_name) if cluster_name
else '')
LOG.debug("Received %(service_name)s service update from %(cluster)s "
"%(host)s: %(cap)s%(cluster)s",
{'service_name': service_name, 'host': host,
'cap': capabilities,
'cluster': cluster_msg})
if just_init:
def notify_service_capabilities(self, service_name, backend, capabilities,
"""Notify the ceilometer with updated volume stats"""
if service_name != 'volume':
updated = []
capa_new = self.service_states.get(backend, {})
timestamp = timestamp or timeutils.utcnow()
# Compare the capabilities and timestamps to decide notifying
if not capa_new:
updated = self._get_updated_pools(capa_new, capabilities)
if timestamp > self.service_states[backend]["timestamp"]:
updated = self._get_updated_pools(
self.service_states[backend], capabilities)
if not updated:
updated = self._get_updated_pools(
self.service_states_last_update.get(backend, {}),
self.service_states.get(backend, {}))
if updated:
capab_copy = dict(capabilities)
capab_copy["timestamp"] = timestamp
# If capabilities changes, notify and record the capabilities.
self.service_states_last_update[backend] = capab_copy
self.get_usage_and_notify(capabilities, updated, backend,
def has_all_capabilities(self):
return len(self._no_capabilities_backends) == 0
def _is_just_initialized(self):
return not self.service_states_last_update
def first_receive_capabilities(self):
return (not self._is_just_initialized() and
len(set(self.backend_state_map)) > 0 and
len(self._no_capabilities_backends) == 0)
def _update_backend_state_map(self, context):
# Get resource usage across the available volume nodes:
topic = constants.VOLUME_TOPIC
volume_services = objects.ServiceList.get_all(context,
{'topic': topic,
'disabled': False,
'frozen': False})
active_backends = set()
active_hosts = set()
no_capabilities_backends = set()
for service in volume_services.objects:
host =
if not service.is_up:
LOG.warning("volume service is down. (host: %s)", host)
backend_key = service.service_topic_queue
# We only pay attention to the first up service of a cluster since
# they all refer to the same capabilities entry in service_states
if backend_key in active_backends:
# Capabilities may come from the cluster or the host if the service
# has just been converted to a cluster service.
capabilities = (self.service_states.get(service.cluster_name, None)
or self.service_states.get(, None))
if capabilities is None:
# Since the service could have been added or remove from a cluster
backend_state = self.backend_state_map.get(backend_key, None)
if not backend_state:
backend_state = self.backend_state_cls(
self.backend_state_map[backend_key] = backend_state
# update capabilities and attributes in backend_state
self._no_capabilities_backends = no_capabilities_backends
# remove non-active keys from backend_state_map
inactive_backend_keys = set(self.backend_state_map) - active_backends
for backend_key in inactive_backend_keys:
# NOTE(geguileo): We don't want to log the removal of a host from
# the map when we are removing it because it has been added to a
# cluster.
if backend_key not in active_hosts:"Removing non-active backend: %(backend)s from "
"scheduler cache.", {'backend': backend_key})
del self.backend_state_map[backend_key]
def revert_volume_consumed_capacity(self, pool_name, size):
for backend_key, state in self.backend_state_map.items():
for key in state.pools:
pool_state = state.pools[key]
if pool_name == '#'.join([backend_key, pool_state.pool_name]):
pool_state.consume_from_volume({'size': -size},
def get_all_backend_states(self, context):
"""Returns a dict of all the backends the HostManager knows about.
Each of the consumable resources in BackendState are
populated with capabilities scheduler received from RPC.
For example:
{'': BackendState(), ...}
# build a pool_state map and return that map instead of
# backend_state_map
all_pools = {}
for backend_key, state in self.backend_state_map.items():
for key in state.pools:
pool = state.pools[key]
# use backend_key.pool_name to make sure key is unique
pool_key = '.'.join([backend_key, pool.pool_name])
all_pools[pool_key] = pool
return all_pools.values()
def _filter_pools_by_volume_type(self, context, volume_type, pools):
"""Return the pools filtered by volume type specs"""
# wrap filter properties only with volume_type
filter_properties = {
'context': context,
'volume_type': volume_type,
'resource_type': volume_type,
'qos_specs': volume_type.get('qos_specs'),
filtered = self.get_filtered_backends(pools.values(),
# filter the pools by value
return {k: v for k, v in pools.items() if v in filtered}
def get_pools(self, context, filters=None):
"""Returns a dict of all pools on all hosts HostManager knows about."""
all_pools = {}
name = volume_type = None
if filters:
name = filters.pop('name', None)
volume_type = filters.pop('volume_type', None)
for backend_key, state in self.backend_state_map.items():
for key in state.pools:
filtered = False
pool = state.pools[key]
# use backend_key.pool_name to make sure key is unique
pool_key = volume_utils.append_host(backend_key,
new_pool = dict(name=pool_key)
if name and new_pool.get('name') != name:
if filters:
# filter all other items in capabilities
for (attr, value) in filters.items():
cap = new_pool.get('capabilities').get(attr)
if not self._equal_after_convert(cap, value):
filtered = True
if not filtered:
all_pools[pool_key] = pool
# filter pools by volume type
if volume_type:
volume_type = volume_types.get_by_name_or_id(
context, volume_type)
all_pools = (
# encapsulate pools in format:{name: XXX, capabilities: XXX}
return [dict(name=key, capabilities=value.capabilities)
for key, value in all_pools.items()]
def get_usage_and_notify(self, capa_new, updated_pools, host, timestamp):
context = cinder_context.get_admin_context()
usage = self._get_usage(capa_new, updated_pools, host, timestamp)
self._notify_capacity_usage(context, usage)
def _get_usage(self, capa_new, updated_pools, host, timestamp):
pools = capa_new.get('pools')
usage = []
if pools and isinstance(pools, list):
backend_usage = dict(type='backend',
# Process the usage.
for pool in pools:
pool_usage = self._get_pool_usage(pool, host, timestamp)
if pool_usage:
backend_usage["total"] += pool_usage["total"]
backend_usage["free"] += pool_usage["free"]
backend_usage["allocated"] += pool_usage["allocated"]
backend_usage["provisioned"] += pool_usage["provisioned"]
backend_usage["virtual_free"] += pool_usage["virtual_free"]
# Only the updated pool is reported.
if pool in updated_pools:
return usage
def _get_pool_usage(self, pool, host, timestamp):
total = pool["total_capacity_gb"]
free = pool["free_capacity_gb"]
unknowns = ["unknown", "infinite", None]
if (total in unknowns) or (free in unknowns):
return {}
allocated = pool["allocated_capacity_gb"]
provisioned = pool["provisioned_capacity_gb"]
reserved = pool["reserved_percentage"]
ratio = utils.calculate_max_over_subscription_ratio(
pool, CONF.max_over_subscription_ratio)
support = pool["thin_provisioning_support"]
virtual_free = utils.calculate_virtual_free_capacity(
pool_usage = dict(
name_to_id='#'.join([host, pool['pool_name']]),
return pool_usage
def _get_updated_pools(self, old_capa, new_capa):
# Judge if the capabilities should be reported.
new_pools = new_capa.get('pools', [])
if not new_pools:
return []
if isinstance(new_pools, list):
# If the volume_stats is not well prepared, don't notify.
if not all(
self.REQUIRED_KEYS.issubset(pool) for pool in new_pools):
return []
LOG.debug("The reported capabilities are not well structured...")
return []
old_pools = old_capa.get('pools', [])
if not old_pools:
return new_pools
updated_pools = []
newpools = {}
oldpools = {}
for new_pool in new_pools:
newpools[new_pool['pool_name']] = new_pool
for old_pool in old_pools:
oldpools[old_pool['pool_name']] = old_pool
for key in newpools:
if key in oldpools.keys():
for k in self.REQUIRED_KEYS:
if newpools[key][k] != oldpools[key][k]:
return updated_pools
def _notify_capacity_usage(self, context, usage):
if usage:
for u in usage:
context, u, u['type'], None, None)
LOG.debug("Publish storage capacity: %s.", usage)
def _equal_after_convert(self, capability, value):
if isinstance(value, type(capability)) or capability is None:
return value == capability
if isinstance(capability, bool):
return capability == strutils.bool_from_string(value)
# We can not check or convert value parameter's type in
# anywhere else.
# If the capability and value are not in the same type,
# we just convert them into string to compare them.
return str(value) == str(capability)
def get_backup_host(self, volume, driver=None):
if volume:
volume_host = volume_utils.extract_host(, 'host')
volume_host = None
az = volume.availability_zone if volume else None
return self._get_available_backup_service_host(volume_host, az, driver)
def _get_any_available_backup_service(self, availability_zone,
"""Get an available backup service host.
Get an available backup service host in the specified
availability zone.
services = [srv for srv in self._list_backup_services(
availability_zone, driver)]
return services[0] if services else None
def _get_available_backup_service_host(self, host, az, driver=None):
"""Return an appropriate backup service host."""
backup_host = None
if not host or not CONF.backup_use_same_host:
backup_host = self._get_any_available_backup_service(az, driver)
elif self._is_backup_service_enabled(az, host):
backup_host = host
if not backup_host:
raise exception.ServiceNotFound(service_id='cinder-backup')
return backup_host
def _list_backup_services(self, availability_zone, driver=None):
"""List all enabled backup services.
:returns: list -- hosts for services that are enabled for backup.
services = []
def _is_good_service(cap, driver, az):
if driver is None and az is None:
return True
match_driver = cap['driver_name'] == driver if driver else True
if match_driver:
if not az:
return True
return cap['availability_zone'] == az
return False
for backend, capabilities in self.backup_service_states.items():
if capabilities['backend_state']:
if _is_good_service(capabilities, driver, availability_zone):
return services
def _az_matched(self, service, availability_zone):
return ((not availability_zone) or
service.availability_zone == availability_zone)
def _is_backup_service_enabled(self, availability_zone, host):
"""Check if there is a backup service available."""
topic = constants.BACKUP_TOPIC
ctxt = cinder_context.get_admin_context()
services = objects.ServiceList.get_all_by_topic(
ctxt, topic, disabled=False)
for srv in services:
if (self._az_matched(srv, availability_zone) and == host and srv.is_up):
return True
return False