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[Bug 1605804] [NEW] Instance creation sometimes fails after host aggregate deletion

To: yahoo-eng-team@xxxxxxxxxxxxxxxxxxx
From: Pooja Ghumre <poojaghumre@xxxxxxxxx>
Date: Fri, 22 Jul 2016 23:50:40 -0000
Reply-to: Bug 1605804 <1605804@xxxxxxxxxxxxxxxxxx>
Sender: bounces@xxxxxxxxxxxxx
Public bug reported:

Instance creation starts failing if nova scheduler gets in an inconsistent state wrt host aggregates. If remove_host_from_aggregate operation is invoked for multiple hosts in quick succession, followed by aggregate deletion, the nova scheduler host_manager maps (host_aggregates_map and aggs_by_id) get out of sync, as there are some stale references left behind in the host_aggregates_map for an aggregate that is deleted from the aggs_by_id map. 
This is because it cleans up state based on aggregate.hosts which is empty when aggregate is deleted, but the prior aggregate updates to remove individual hosts could have incorrect list of hosts added to the host_aggregates_map.

Instance creation fails with below error once scheduler gets in this state:
2016-07-21 18:20:16.780 15692 ERROR oslo_messaging.rpc.dispatcher [req-7f29701b-0272-444c-8650-a1035777e642 d2c755daa21e451e86c1d2b5be705aa2 0546d7f9c747456aa0ffb306cfe5627d - - -] Exception during message handling: 1
2016-07-21 18:20:16.780 15692 ERROR oslo_messaging.rpc.dispatcher Traceback (most recent call last):
2016-07-21 18:20:16.780 15692 ERROR oslo_messaging.rpc.dispatcher   File "/opt/pf9/nova/lib/python2.7/site-packages/oslo_messaging/rpc/dispatcher.py", line 138, in _dispatch_and_reply
2016-07-21 18:20:16.780 15692 ERROR oslo_messaging.rpc.dispatcher     incoming.message))
2016-07-21 18:20:16.780 15692 ERROR oslo_messaging.rpc.dispatcher   File "/opt/pf9/nova/lib/python2.7/site-packages/oslo_messaging/rpc/dispatcher.py", line 183, in _dispatch
2016-07-21 18:20:16.780 15692 ERROR oslo_messaging.rpc.dispatcher     return self._do_dispatch(endpoint, method, ctxt, args)
2016-07-21 18:20:16.780 15692 ERROR oslo_messaging.rpc.dispatcher   File "/opt/pf9/nova/lib/python2.7/site-packages/oslo_messaging/rpc/dispatcher.py", line 127, in _do_dispatch
2016-07-21 18:20:16.780 15692 ERROR oslo_messaging.rpc.dispatcher     result = func(ctxt, **new_args)
2016-07-21 18:20:16.780 15692 ERROR oslo_messaging.rpc.dispatcher   File "/opt/pf9/nova/lib/python2.7/site-packages/oslo_messaging/rpc/server.py", line 150, in inner
2016-07-21 18:20:16.780 15692 ERROR oslo_messaging.rpc.dispatcher     return func(*args, **kwargs)
2016-07-21 18:20:16.780 15692 ERROR oslo_messaging.rpc.dispatcher   File "/opt/pf9/nova/lib/python2.7/site-packages/nova/scheduler/manager.py", line 84, in select_destinations
2016-07-21 18:20:16.780 15692 ERROR oslo_messaging.rpc.dispatcher     filter_properties)
2016-07-21 18:20:16.780 15692 ERROR oslo_messaging.rpc.dispatcher   File "/opt/pf9/nova/lib/python2.7/site-packages/nova/scheduler/filter_scheduler.py", line 72, in select_destinations
2016-07-21 18:20:16.780 15692 ERROR oslo_messaging.rpc.dispatcher     filter_properties)
2016-07-21 18:20:16.780 15692 ERROR oslo_messaging.rpc.dispatcher   File "/opt/pf9/nova/lib/python2.7/site-packages/nova/scheduler/filter_scheduler.py", line 164, in _schedule
2016-07-21 18:20:16.780 15692 ERROR oslo_messaging.rpc.dispatcher     hosts = self._get_all_host_states(elevated)
2016-07-21 18:20:16.780 15692 ERROR oslo_messaging.rpc.dispatcher   File "/opt/pf9/nova/lib/python2.7/site-packages/nova/scheduler/filter_scheduler.py", line 222, in _get_all_host_states
2016-07-21 18:20:16.780 15692 ERROR oslo_messaging.rpc.dispatcher     return self.host_manager.get_all_host_states(context)
2016-07-21 18:20:16.780 15692 ERROR oslo_messaging.rpc.dispatcher   File "/opt/pf9/nova/lib/python2.7/site-packages/nova/scheduler/host_manager.py", line 585, in get_all_host_states
2016-07-21 18:20:16.780 15692 ERROR oslo_messaging.rpc.dispatcher     host_state.host]]
2016-07-21 18:20:16.780 15692 ERROR oslo_messaging.rpc.dispatcher KeyError: 1
2016-07-21 18:20:16.780 15692 ERROR oslo_messaging.rpc.dispatcher
2016-07-21 18:20:16.784 15692 ERROR oslo_messaging._drivers.common [req-7f29701b-0272-444c-8650-a1035777e642 d2c755daa21e451e86c1d2b5be705aa2 0546d7f9c747456aa0ffb306cfe5627d - - -] Returning exception 1 to caller

** Affects: nova
     Importance: Undecided
         Status: New

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https://bugs.launchpad.net/bugs/1605804

Title:
  Instance creation sometimes fails after host aggregate deletion

Status in OpenStack Compute (nova):
  New

Bug description:
  Instance creation starts failing if nova scheduler gets in an inconsistent state wrt host aggregates. If remove_host_from_aggregate operation is invoked for multiple hosts in quick succession, followed by aggregate deletion, the nova scheduler host_manager maps (host_aggregates_map and aggs_by_id) get out of sync, as there are some stale references left behind in the host_aggregates_map for an aggregate that is deleted from the aggs_by_id map. 
  This is because it cleans up state based on aggregate.hosts which is empty when aggregate is deleted, but the prior aggregate updates to remove individual hosts could have incorrect list of hosts added to the host_aggregates_map.

  Instance creation fails with below error once scheduler gets in this state:
  2016-07-21 18:20:16.780 15692 ERROR oslo_messaging.rpc.dispatcher [req-7f29701b-0272-444c-8650-a1035777e642 d2c755daa21e451e86c1d2b5be705aa2 0546d7f9c747456aa0ffb306cfe5627d - - -] Exception during message handling: 1
  2016-07-21 18:20:16.780 15692 ERROR oslo_messaging.rpc.dispatcher Traceback (most recent call last):
  2016-07-21 18:20:16.780 15692 ERROR oslo_messaging.rpc.dispatcher   File "/opt/pf9/nova/lib/python2.7/site-packages/oslo_messaging/rpc/dispatcher.py", line 138, in _dispatch_and_reply
  2016-07-21 18:20:16.780 15692 ERROR oslo_messaging.rpc.dispatcher     incoming.message))
  2016-07-21 18:20:16.780 15692 ERROR oslo_messaging.rpc.dispatcher   File "/opt/pf9/nova/lib/python2.7/site-packages/oslo_messaging/rpc/dispatcher.py", line 183, in _dispatch
  2016-07-21 18:20:16.780 15692 ERROR oslo_messaging.rpc.dispatcher     return self._do_dispatch(endpoint, method, ctxt, args)
  2016-07-21 18:20:16.780 15692 ERROR oslo_messaging.rpc.dispatcher   File "/opt/pf9/nova/lib/python2.7/site-packages/oslo_messaging/rpc/dispatcher.py", line 127, in _do_dispatch
  2016-07-21 18:20:16.780 15692 ERROR oslo_messaging.rpc.dispatcher     result = func(ctxt, **new_args)
  2016-07-21 18:20:16.780 15692 ERROR oslo_messaging.rpc.dispatcher   File "/opt/pf9/nova/lib/python2.7/site-packages/oslo_messaging/rpc/server.py", line 150, in inner
  2016-07-21 18:20:16.780 15692 ERROR oslo_messaging.rpc.dispatcher     return func(*args, **kwargs)
  2016-07-21 18:20:16.780 15692 ERROR oslo_messaging.rpc.dispatcher   File "/opt/pf9/nova/lib/python2.7/site-packages/nova/scheduler/manager.py", line 84, in select_destinations
  2016-07-21 18:20:16.780 15692 ERROR oslo_messaging.rpc.dispatcher     filter_properties)
  2016-07-21 18:20:16.780 15692 ERROR oslo_messaging.rpc.dispatcher   File "/opt/pf9/nova/lib/python2.7/site-packages/nova/scheduler/filter_scheduler.py", line 72, in select_destinations
  2016-07-21 18:20:16.780 15692 ERROR oslo_messaging.rpc.dispatcher     filter_properties)
  2016-07-21 18:20:16.780 15692 ERROR oslo_messaging.rpc.dispatcher   File "/opt/pf9/nova/lib/python2.7/site-packages/nova/scheduler/filter_scheduler.py", line 164, in _schedule
  2016-07-21 18:20:16.780 15692 ERROR oslo_messaging.rpc.dispatcher     hosts = self._get_all_host_states(elevated)
  2016-07-21 18:20:16.780 15692 ERROR oslo_messaging.rpc.dispatcher   File "/opt/pf9/nova/lib/python2.7/site-packages/nova/scheduler/filter_scheduler.py", line 222, in _get_all_host_states
  2016-07-21 18:20:16.780 15692 ERROR oslo_messaging.rpc.dispatcher     return self.host_manager.get_all_host_states(context)
  2016-07-21 18:20:16.780 15692 ERROR oslo_messaging.rpc.dispatcher   File "/opt/pf9/nova/lib/python2.7/site-packages/nova/scheduler/host_manager.py", line 585, in get_all_host_states
  2016-07-21 18:20:16.780 15692 ERROR oslo_messaging.rpc.dispatcher     host_state.host]]
  2016-07-21 18:20:16.780 15692 ERROR oslo_messaging.rpc.dispatcher KeyError: 1
  2016-07-21 18:20:16.780 15692 ERROR oslo_messaging.rpc.dispatcher
  2016-07-21 18:20:16.784 15692 ERROR oslo_messaging._drivers.common [req-7f29701b-0272-444c-8650-a1035777e642 d2c755daa21e451e86c1d2b5be705aa2 0546d7f9c747456aa0ffb306cfe5627d - - -] Returning exception 1 to caller

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Follow ups

[Bug 1605804] Re: Instance creation sometimes fails after host aggregate deletion
From: Matt Riedemann, 2016-10-15
[Bug 1605804] Re: Instance creation sometimes fails after host aggregate deletion
From: OpenStack Infra, 2016-09-06