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Add generic reproducer for bug #1879878

No need for the libvirt driver in all its complexity here.

Change-Id: Ifea9a15fb01c0b25e9973024f4f61faecc56e1cd
Signed-off-by: Stephen Finucane <stephenfin@redhat.com>
(cherry picked from commit e1adbced92)
changes/50/751350/1
Stephen Finucane 1 month ago
parent
commit
15da841ecb
1 changed files with 168 additions and 0 deletions
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      nova/tests/functional/regressions/test_bug_1879878.py

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nova/tests/functional/regressions/test_bug_1879878.py View File

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# 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.

import ddt

from nova.compute import resource_tracker as rt
from nova import context as nova_context
from nova import objects
from nova.tests.functional import integrated_helpers


@ddt.ddt
class TestColdMigrationUsage(integrated_helpers.ProviderUsageBaseTestCase):
"""Reproducer for bug #1879878.

Demonstrate the possibility of races caused by running the resource
tracker's periodic task between marking a migration as confirmed or
reverted and dropping the claim for that migration on the source or
destination host, respectively.
"""
compute_driver = 'fake.MediumFakeDriver'

def setUp(self):
super().setUp()
# Start two computes so we can migrate between them.
self._start_compute('host1')
self._start_compute('host2')

self.ctxt = nova_context.get_admin_context()

def _create_server(self):
"""Creates and return a server along with a source host and target
host.
"""
server = super()._create_server(networks='none')
self.addCleanup(self._delete_server, server)
source_host = server['OS-EXT-SRV-ATTR:host']
target_host = 'host2' if source_host == 'host1' else 'host1'
return server, source_host, target_host

def assertUsage(self, hostname, usage):
"""Assert VCPU usage for the given host."""
cn = objects.ComputeNode.get_by_nodename(self.ctxt, hostname)
# we could test anything, but vcpu is easy to grok
self.assertEqual(cn.vcpus_used, usage)

@ddt.data(True, False)
def test_migrate_confirm(self, drop_race):
server, src_host, dst_host = self._create_server()

# only one instance created, so usage on its host
self.assertUsage(src_host, 1)
self.assertUsage(dst_host, 0)

orig_drop_claim = rt.ResourceTracker.drop_move_claim

def fake_drop_move_claim(*args, **kwargs):
# run periodics after marking the migration confirmed, simulating a
# race between the doing this and actually dropping the claim

# check the usage, which should show usage on both hosts
self.assertUsage(src_host, 1)
self.assertUsage(dst_host, 1)

if drop_race:
self._run_periodics()

# FIXME(stephenfin): the periodic should not have dropped the
# records for the src yet
self.assertUsage(src_host, 0)
self.assertUsage(dst_host, 1)

return orig_drop_claim(*args, **kwargs)

self.stub_out(
'nova.compute.resource_tracker.ResourceTracker.drop_move_claim',
fake_drop_move_claim,
)

# TODO(stephenfin): Use a helper
self.api.post_server_action(server['id'], {'migrate': None})
self._wait_for_state_change(server, 'VERIFY_RESIZE')

# migration isn't complete so we should have usage on both hosts
self.assertUsage(src_host, 1)
self.assertUsage(dst_host, 1)

self._confirm_resize(server)

# migration is now confirmed so we should once again only have usage on
# one host
# FIXME(stephenfin): Our usage here should be 0 and 1 for source and
# dest respectively when confirming, but that won't happen until we run
# the periodic and rebuild our inventory from scratch
self.assertUsage(src_host, -1 if drop_race else 0)
self.assertUsage(dst_host, 1)

# running periodics shouldn't change things
self._run_periodics()

self.assertUsage(src_host, 0)
self.assertUsage(dst_host, 1)

@ddt.data(True, False)
def test_migrate_revert(self, drop_race):
server, src_host, dst_host = self._create_server()

# only one instance created, so usage on its host
self.assertUsage(src_host, 1)
self.assertUsage(dst_host, 0)

orig_drop_claim = rt.ResourceTracker.drop_move_claim

def fake_drop_move_claim(*args, **kwargs):
# run periodics after marking the migration reverted, simulating a
# race between the doing this and actually dropping the claim

# check the usage, which should show usage on both hosts
self.assertUsage(src_host, 1)
self.assertUsage(dst_host, 1)

if drop_race:
self._run_periodics()

# FIXME(stephenfin): the periodic should not have dropped the
# records for the src
self.assertUsage(src_host, 0)
self.assertUsage(dst_host, 1)

return orig_drop_claim(*args, **kwargs)

self.stub_out(
'nova.compute.resource_tracker.ResourceTracker.drop_move_claim',
fake_drop_move_claim,
)

# TODO(stephenfin): Use a helper
self.api.post_server_action(server['id'], {'migrate': None})
self._wait_for_state_change(server, 'VERIFY_RESIZE')

# migration isn't complete so we should have usage on both hosts
self.assertUsage(src_host, 1)
self.assertUsage(dst_host, 1)

self._revert_resize(server)

# migration is now reverted so we should once again only have usage on
# one host
# FIXME(stephenfin): Our usage here should always be 1 and 0 for source
# and dest respectively when reverting, but that won't happen until we
# run the periodic and rebuild our inventory from scratch
self.assertUsage(src_host, 0 if drop_race else 1)
self.assertUsage(dst_host, 1 if drop_race else 0)

# running periodics shouldn't change things
self._run_periodics()

self.assertUsage(src_host, 1)
self.assertUsage(dst_host, 0)

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