nova/releasenotes/notes/bug-1856925-check-source-compute-resize-16e9c3b24cf72301.yaml
Matt Riedemann ea2ea492a3 Ensure source service is up before resizing/migrating
If the source compute service is down when a resize or
cold migrate is initiated the prep_resize cast from the
selected destination compute service to the source will
fail/hang. The API can validate the source compute service
is up or fail the operation with a 409 response if the
source service is down. Note that a host status of
"MAINTENANCE" means the service is up but disabled by
an administrator which is OK for resize/cold migrate.

The solution here works the validation into the
check_instance_host decorator which surprisingly isn't
used in more places where the source host is involved
like reboot, rebuild, snapshot, etc. This change just
handles the resize method but is done in such a way that
the check_instance_host decorator could be applied to
those other methods and perform the is-up check as well.
The decorator is made backward compatible by default.

Note that Instance._save_services is added because during
resize the Instance is updated and the services field
is set but not actually changed, but Instance.save()
handles object fields differently so we need to implement
the no-op _save_services method to avoid a failure.

Change-Id: I85423c7bcacff3bc465c22686d0675529d211b59
Closes-Bug: #1856925
2019-12-19 15:24:34 -05:00

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YAML

---
fixes:
- |
This release contains a fix for `bug 1856925`_ such that ``resize`` and
``migrate`` server actions will be rejected with a 409 ``HTTPConflict``
response if the source compute service is down.
.. _bug 1856925: https://bugs.launchpad.net/nova/+bug/1856925