OpenStack Compute (Nova)
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Artom Lifshitz 64b4271279 Revert "Handle Neutron errors in _post_live_migration()"
This reverts commit 9f205c620e.

There's a lot of context here, so strap in for a long read.

There are two unrelated bugs, but they intersect in their fixes.

First, a bit of history. In Rocky, as part of the
bp/neutron-new-port-binding-api blueprint, we started using Neutron's
extended port binding API during live migration [1]. In short, that
API allows a port to be bound to two hosts (source and destination),
with the binding being active on only one. Not all versions and
configurations of Neutron support the extended port binding API, so
Nova needed a sentinel to determine whether the extended port binding
API was in use during a live migration. The `migrate_data.vifs` OVO
field was that sentinel [2]. Its presence indicated that Neutron's
extended port binding API was being used.

When SRIOV live migration was added in Train [3], it started
unconditionally setting `migrate_data.vifs` [4]. In cases where
Neutron did not support the extended port binding API, this resulted
in incorrect information in `migrate_data.vifs`. The source vif
information was correct, but, without the ability in Neutron to have
port binding on both the source and the destination, the destination
vif information was missing. This causes libvirt's
_pre_live_migration_plug_vifs() method (introduced in the same
bp/neutron-new-port-binding-api series as [1]) to explode when it
attempts to get the destination vifs [5]. This is bug 1888395, and is
being fixed in [6] by no longer unconditionally setting
`migrate_data.vifs`, and only setting it if Neutron supports the
extended port binding API.

How is any of this relevant to the fix for bug 1879787, which is
what's being reverted here? First, some context refresher.

In bug 1879787, the call to network_api.get_instance_nw_info() in
_post_live_migration() on the source compute manager eventually calls
out to the Neutron REST API. If this fails, the exception is
unhandled, and the migrating instance - which is fully running on the
destination at this point - will never be updated in the database.
This update normally happens later in

The network_info variable obtained from get_instance_nw_info() is used
for two things: notifications - which aren't critical - and unplugging
the instance's vifs on the source - which is very important!

The latter is done in a call to
driver.post_live_migration_at_source(), which is passed unplug_nw_info
to tell it which vifs to unplug. unplug_nw_info contains either
network_info, or is constructed from `migrate_data.vifs` if
`migrate_data.vifs` exists. Based on [4], `migrate_data.vifs` was
assumed to always exist. When [6] merges, this will no longer be the
case.  Thus, a different fix for bug 1879787 is needed, and the
previously merged one needs to be reverted.





Change-Id: Ifa360b3ab2873fd94afdce1faddf61ff9d06163f
2020-09-01 10:57:18 -04:00
api-guide/source Fix pygments_style 2020-05-20 21:56:41 +02:00
api-ref/source compute: Validate a BDMs disk_bus when provided 2020-07-29 16:05:48 +00:00
devstack Merge "Find instance in another cell during floating IP re-association" 2019-09-13 15:19:55 +00:00
doc Provider Config File: Enable loading and merging of provider configs 2020-08-26 23:18:53 +08:00
etc/nova Allow versioned discovery unauthenticated 2020-04-03 21:24:28 +00:00
gate nova-live-migration: Only stop n-cpu and q-agt during evacuation testing 2020-03-21 17:08:47 +00:00
nova Revert "Handle Neutron errors in _post_live_migration()" 2020-09-01 10:57:18 -04:00
playbooks Make our ceph job test with glance in multistore mode 2020-07-14 09:11:42 -07:00
releasenotes Merge "Provider Config File: Enable loading and merging of provider configs" 2020-08-27 05:10:11 +00:00
roles Enable cross-cell resize in the nova-multi-cell job 2019-12-23 10:10:57 -05:00
tools Merge "Fix user creation with GRANT in MySQL 8.0(Ubuntu Focal)" 2020-07-02 18:40:46 +00:00
.coveragerc Remove nova/openstack/* from .coveragerc 2016-10-12 16:20:49 -04:00
.gitignore tox: Integrate mypy 2020-05-15 15:59:53 +01:00
.gitreview OpenDev Migration Patch 2019-04-19 19:45:52 +00:00
.mailmap Add mailmap entry 2014-05-07 12:14:26 -07:00
.pre-commit-config.yaml Switch to hacking 2.x 2020-01-17 11:30:40 +00:00
.stestr.conf Finish stestr migration 2017-11-24 16:51:12 -05:00
.zuul.yaml zuul: use the new barbican simple-crypto job 2020-08-17 20:09:47 +02:00
CONTRIBUTING.rst [Community goal] Update contributor documentation 2020-03-25 12:01:37 +00:00
HACKING.rst Remove hacking rules for python 2/3 compatibility 2020-06-17 08:19:13 +00:00
LICENSE initial commit 2010-05-27 23:05:26 -07:00
MAINTAINERS Fix broken URLs 2017-09-07 15:42:31 +02:00
README.rst Start README.rst with a better title 2019-11-19 17:29:28 +01:00
bindep.txt Add lsscsi to bindep 2020-08-05 16:16:49 -05:00
lower-constraints.txt [goal] Prepare for job migration to Ubuntu Focal (20.04) 2020-08-18 11:28:32 +00:00
mypy-files.txt Add type hints to 'nova.compute.manager' 2020-08-26 09:45:13 +01:00
requirements.txt [goal] Prepare for job migration to Ubuntu Focal (20.04) 2020-08-18 11:28:32 +00:00
setup.cfg tox: Integrate mypy 2020-05-15 15:59:53 +01:00 Updated from global requirements 2017-03-02 11:50:48 +00:00
test-requirements.txt [goal] Prepare for job migration to Ubuntu Focal (20.04) 2020-08-18 11:28:32 +00:00
tox.ini Remove hacking rules for python 2/3 compatibility 2020-06-17 08:19:13 +00:00


OpenStack Nova


OpenStack Nova provides a cloud computing fabric controller, supporting a wide variety of compute technologies, including: libvirt (KVM, Xen, LXC and more), Hyper-V, VMware, XenServer, OpenStack Ironic and PowerVM.

Use the following resources to learn more.


To learn how to use Nova's API, consult the documentation available online at:

For more information on OpenStack APIs, SDKs and CLIs in general, refer to:


To learn how to deploy and configure OpenStack Nova, consult the documentation available online at:

In the unfortunate event that bugs are discovered, they should be reported to the appropriate bug tracker. If you obtained the software from a 3rd party operating system vendor, it is often wise to use their own bug tracker for reporting problems. In all other cases use the master OpenStack bug tracker, available at:


For information on how to contribute to Nova, please see the contents of the CONTRIBUTING.rst.

Any new code must follow the development guidelines detailed in the HACKING.rst file, and pass all unit tests.

Further developer focused documentation is available at:

Other Information

During each Summit and Project Team Gathering, we agree on what the whole community wants to focus on for the upcoming release. The plans for nova can be found at: