OpenStack Compute (Nova)
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Stephen Finucane 44376d2e21 Don't unset Instance.old_flavor, new_flavor until necessary
Since change Ia6d8a7909081b0b856bd7e290e234af7e42a2b38, the resource
tracker's 'drop_move_claim' method has been capable of freeing up
resource usage. However, this relies on accurate resource reporting.
It transpires that there's a race whereby the resource tracker's
'update_available_resource' periodic task can end up not accounting for
usage from migrations that are in the process of being completed. The
root cause is the resource tracker's reliance on the stashed flavor in a
given migration record [1]. Previously, this information was deleted by
the compute manager at the start of the confirm migration operation [2].
The compute manager would then call the virt driver [3], which could
take a not insignificant amount of time to return, before finally
dropping the move claim. If the periodic task ran between the clearing
of the stashed flavor and the return of the virt driver, it would find a
migration record with no stashed flavor and would therefore ignore this
record for accounting purposes [4], resulting in an incorrect record for
the compute node, and an exception when the 'drop_move_claim' attempts
to free up the resources that aren't being tracked.

The solution to this issue is pretty simple. Instead of unsetting the
old flavor record from the migration at the start of the various move
operations, do it afterwards.

[1] https://github.com/openstack/nova/blob/6557d67/nova/compute/resource_tracker.py#L1288
[2] https://github.com/openstack/nova/blob/6557d67/nova/compute/manager.py#L4310-L4315
[3] https://github.com/openstack/nova/blob/6557d67/nova/compute/manager.py#L4330-L4331
[4] https://github.com/openstack/nova/blob/6557d67/nova/compute/resource_tracker.py#L1300

Change-Id: I4760b01b695c94fa371b72216d398388cf981d28
Signed-off-by: Stephen Finucane <stephenfin@redhat.com>
Partial-Bug: #1879878
Related-Bug: #1834349
Related-Bug: #1818914
2020-09-01 16:19:27 +01:00
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 doc: Update references to image properties 2020-08-31 11:59:14 +01:00
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 Don't unset Instance.old_flavor, new_flavor until necessary 2020-09-01 16:19:27 +01:00
playbooks Make our ceph job test with glance in multistore mode 2020-07-14 09:11:42 -07:00
releasenotes Merge "QEMU/KVM: accept vmxnet3 NIC" 2020-08-30 12:55:42 +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 Merge "zuul: Start to migrate nova-live-migration to zuulv3" 2020-08-28 09:40:27 +00:00
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
setup.py 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

README.rst

OpenStack Nova

image

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.

API

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:

Operators

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:

Developers

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: