deb-cinder/cinder/scheduler/driver.py
Michał Dulko c9a55d852e Add SIGHUP handlers to reset RPC version pins
Adding SIGHUP handlers (by implementing reset from oslo.service) to
cinder-scheduler, cinder-backup and cinder-volume that reset cached RPC
version pins. This is to avoid the need to restart all the services when
upgrade of the deployment is completed.

Some changes go a little deep into the stack, because to reload all the
pins we need to recreate <service>.rpcapi.<service>API objects that are
stored in the memory.

Please note that SIGHUP signal is handled by oslo.service only when
service runs in daemon mode (without tty attached). To test this commit
in DevStack you need to add "&" to the end of the command that starts
the service.

Situation is more complicated with the API service, so we're leaving it
with restart required for now. In the deployments with HA cinder-api is
typically behind a load balancer, so restarting individual nodes
one-by-one should be easy.

DocImpact: Add information on rolling upgrades procedures to the docs.
Implements: blueprint rpc-object-compatibility

Change-Id: I03ed74e17dc9a4b9aa2ddcfbeb36a106a0f035f8
2016-02-19 10:30:17 +01:00

124 lines
4.6 KiB
Python

# Copyright (c) 2010 OpenStack Foundation
# Copyright 2010 United States Government as represented by the
# Administrator of the National Aeronautics and Space Administration.
# 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
#
# http://www.apache.org/licenses/LICENSE-2.0
#
# 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.
"""
Scheduler base class that all Schedulers should inherit from
"""
from oslo_config import cfg
from oslo_utils import importutils
from oslo_utils import timeutils
from cinder.i18n import _
from cinder import objects
from cinder.volume import rpcapi as volume_rpcapi
scheduler_driver_opts = [
cfg.StrOpt('scheduler_host_manager',
default='cinder.scheduler.host_manager.HostManager',
help='The scheduler host manager class to use'),
cfg.IntOpt('scheduler_max_attempts',
default=3,
help='Maximum number of attempts to schedule a volume'),
]
CONF = cfg.CONF
CONF.register_opts(scheduler_driver_opts)
def volume_update_db(context, volume_id, host):
"""Set the host and set the scheduled_at field of a volume.
:returns: A Volume with the updated fields set properly.
"""
volume = objects.Volume.get_by_id(context, volume_id)
volume.host = host
volume.scheduled_at = timeutils.utcnow()
volume.save()
# A volume object is expected to be returned, as it is used by
# filter_scheduler.
return volume
def group_update_db(context, group, host):
"""Set the host and the scheduled_at field of a consistencygroup.
:returns: A Consistencygroup with the updated fields set properly.
"""
group.update({'host': host, 'updated_at': timeutils.utcnow()})
group.save()
return group
class Scheduler(object):
"""The base class that all Scheduler classes should inherit from."""
def __init__(self):
self.host_manager = importutils.import_object(
CONF.scheduler_host_manager)
self.volume_rpcapi = volume_rpcapi.VolumeAPI()
def reset(self):
"""Reset volume RPC API object to load new version pins."""
self.volume_rpcapi = volume_rpcapi.VolumeAPI()
def is_ready(self):
"""Returns True if Scheduler is ready to accept requests.
This is to handle scheduler service startup when it has no volume hosts
stats and will fail all the requests.
"""
return self.host_manager.has_all_capabilities()
def update_service_capabilities(self, service_name, host, capabilities):
"""Process a capability update from a service node."""
self.host_manager.update_service_capabilities(service_name,
host,
capabilities)
def host_passes_filters(self, context, volume_id, host, filter_properties):
"""Check if the specified host passes the filters."""
raise NotImplementedError(_("Must implement host_passes_filters"))
def find_retype_host(self, context, request_spec, filter_properties=None,
migration_policy='never'):
"""Find a host that can accept the volume with its new type."""
raise NotImplementedError(_("Must implement find_retype_host"))
def schedule(self, context, topic, method, *_args, **_kwargs):
"""Must override schedule method for scheduler to work."""
raise NotImplementedError(_("Must implement a fallback schedule"))
def schedule_create_volume(self, context, request_spec, filter_properties):
"""Must override schedule method for scheduler to work."""
raise NotImplementedError(_("Must implement schedule_create_volume"))
def schedule_create_consistencygroup(self, context, group,
request_spec_list,
filter_properties_list):
"""Must override schedule method for scheduler to work."""
raise NotImplementedError(_(
"Must implement schedule_create_consistencygroup"))
def get_pools(self, context, filters):
"""Must override schedule method for scheduler to work."""
raise NotImplementedError(_(
"Must implement schedule_get_pools"))