f7c688b8ef
This aims to fix the issue described in bug 1664931 where a rebuild fails to validate the existing host with the scheduler when a new image is provided. The previous attempt to do this could cause rebuilds to fail unnecessarily because we ran _all_ of the filters during a rebuild, which could cause usage/resource filters to prevent an otherwise valid rebuild from succeeding. This aims to classify filters as useful for rebuild or not, and only apply the former during a rebuild scheduler check. We do this by using an internal scheduler hint, indicating our intent. This should (a) filter out all hosts other than the one we're running on and (b) be detectable by the filtering infrastructure as an internally-generated scheduling request in order to trigger the correct filtering behavior. Closes-Bug: #1664931 Change-Id: I1a46ef1503be2febcd20f4594f44344d05525446
65 lines
2.4 KiB
Python
65 lines
2.4 KiB
Python
# Copyright (c) 2011 OpenStack Foundation
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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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Scheduler host filters
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"""
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from nova import filters
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class BaseHostFilter(filters.BaseFilter):
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"""Base class for host filters."""
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# This is set to True if this filter should be run for rebuild.
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# For example, with rebuild, we need to ask the scheduler if the
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# existing host is still legit for a rebuild with the new image and
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# other parameters. We care about running policy filters (i.e.
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# ImagePropertiesFilter) but not things that check usage on the
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# existing compute node, etc.
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RUN_ON_REBUILD = False
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def _filter_one(self, obj, spec):
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"""Return True if the object passes the filter, otherwise False."""
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# Do this here so we don't get scheduler.filters.utils
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from nova.scheduler import utils
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if not self.RUN_ON_REBUILD and utils.request_is_rebuild(spec):
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# If we don't filter, default to passing the host.
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return True
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else:
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# We are either a rebuild filter, in which case we always run,
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# or this request is not rebuild in which case all filters
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# should run.
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return self.host_passes(obj, spec)
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def host_passes(self, host_state, filter_properties):
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"""Return True if the HostState passes the filter, otherwise False.
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Override this in a subclass.
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"""
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raise NotImplementedError()
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class HostFilterHandler(filters.BaseFilterHandler):
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def __init__(self):
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super(HostFilterHandler, self).__init__(BaseHostFilter)
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def all_filters():
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"""Return a list of filter classes found in this directory.
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This method is used as the default for available scheduler filters
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and should return a list of all filter classes available.
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"""
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return HostFilterHandler().get_all_classes()
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