0f67836de2
When hosts are filtered for a request, and no host passes all the filters, operators can only see the last filter run; they have no visibility into which filter removed which host. This attempts to improve this situation by tracking the hosts remaining after each filter is run and the number of hosts removed. If no host is left, to log that information along with the reservation ID and instance UUID of the request. Since that can be a lot of information, it will call LOG.info with just the counts for all but the final filter, which will contain the last deleted host names; LOG.debug will output the full record of each filter and the hosts remaining after each step. This will better enable operators to determine why a particular host was not selected. Change-Id: I6173274a03bd8712eb4d63c7a998bb02abdecf4b Blueprint: no-valid-host-reporting
125 lines
5.3 KiB
Python
125 lines
5.3 KiB
Python
# Copyright (c) 2011-2012 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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Filter support
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"""
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from oslo_log import log as logging
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from nova.i18n import _LI
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from nova import loadables
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LOG = logging.getLogger(__name__)
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class BaseFilter(object):
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"""Base class for all filter classes."""
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def _filter_one(self, obj, filter_properties):
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"""Return True if it passes the filter, False otherwise.
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Override this in a subclass.
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"""
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return True
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def filter_all(self, filter_obj_list, filter_properties):
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"""Yield objects that pass the filter.
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Can be overridden in a subclass, if you need to base filtering
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decisions on all objects. Otherwise, one can just override
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_filter_one() to filter a single object.
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"""
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for obj in filter_obj_list:
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if self._filter_one(obj, filter_properties):
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yield obj
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# Set to true in a subclass if a filter only needs to be run once
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# for each request rather than for each instance
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run_filter_once_per_request = False
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def run_filter_for_index(self, index):
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"""Return True if the filter needs to be run for the "index-th"
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instance in a request. Only need to override this if a filter
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needs anything other than "first only" or "all" behaviour.
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"""
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if self.run_filter_once_per_request and index > 0:
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return False
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else:
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return True
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class BaseFilterHandler(loadables.BaseLoader):
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"""Base class to handle loading filter classes.
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This class should be subclassed where one needs to use filters.
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"""
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def get_filtered_objects(self, filters, objs, filter_properties, index=0):
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list_objs = list(objs)
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LOG.debug("Starting with %d host(s)", len(list_objs))
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# Track the hosts as they are removed. The 'full_filter_results' list
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# contains the host/nodename info for every host that passes each
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# filter, while the 'part_filter_results' list just tracks the number
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# removed by each filter, unless the filter returns zero hosts, in
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# which case it records the host/nodename for the last batch that was
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# removed. Since the full_filter_results can be very large, it is only
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# recorded if the LOG level is set to debug.
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part_filter_results = []
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full_filter_results = []
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log_msg = "%(cls_name)s: (start: %(start)s, end: %(end)s)"
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for filter_ in filters:
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if filter_.run_filter_for_index(index):
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cls_name = filter_.__class__.__name__
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start_count = len(list_objs)
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objs = filter_.filter_all(list_objs, filter_properties)
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if objs is None:
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LOG.debug("Filter %s says to stop filtering", cls_name)
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return
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list_objs = list(objs)
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end_count = len(list_objs)
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part_filter_results.append(log_msg % {"cls_name": cls_name,
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"start": start_count, "end": end_count})
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if list_objs:
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remaining = [(getattr(obj, "host", obj),
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getattr(obj, "nodename", ""))
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for obj in list_objs]
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full_filter_results.append((cls_name, remaining))
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else:
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LOG.info(_LI("Filter %s returned 0 hosts"), cls_name)
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full_filter_results.append((cls_name, None))
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break
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LOG.debug("Filter %(cls_name)s returned "
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"%(obj_len)d host(s)",
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{'cls_name': cls_name, 'obj_len': len(list_objs)})
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if not list_objs:
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# Log the filtration history
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rspec = filter_properties.get("request_spec", {})
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inst_props = rspec.get("instance_properties", {})
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msg_dict = {"res_id": inst_props.get("reservation_id", ""),
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"inst_uuid": inst_props.get("uuid", ""),
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"str_results": str(full_filter_results),
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}
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full_msg = ("Filtering removed all hosts for the request with "
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"reservation ID '%(res_id)s' and instance ID "
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"'%(inst_uuid)s'. Filter results: %(str_results)s"
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) % msg_dict
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msg_dict["str_results"] = str(part_filter_results)
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part_msg = _LI("Filtering removed all hosts for the request with "
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"reservation ID '%(res_id)s' and instance ID "
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"'%(inst_uuid)s'. Filter results: %(str_results)s"
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) % msg_dict
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LOG.debug(full_msg)
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LOG.info(part_msg)
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return list_objs
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