Confirm migration fails when executed with "nova migrate" instead of "nova resize"

[Alessandro Pilotti]

Cold migration fails when executed with "nova migrate <id>" and followed by "nova resize-confirm <id>" or "nova resize-revert <id>" with the following error:

http://paste.openstack.org/show/32680/

[Feilong Wang (flwang)]

This issue is caused by deleting the non-existed metadata with prefix "old_" in function confirm_resize().

Based on current implement, when calling "nova migrate <server>" with allow_resize_to_same_host=true and there is only one host, No metadata with prefix 'old_' will be saved. But on calling "resize-confirm", confirm_resize() will try to delete both the metadata with prefix 'old_' and 'new_ '. Then user will run into exception which said: "KeyError: 'old_instance_type_memory_mb'"

So I'm going to submit a fix to make sure the metadata with prefix "old_" will be savid in _finish_resize() to avoid the exception.

[OpenStack Infra (hudson-openstack)]

Fix proposed to branch: master
Review: https://review.openstack.org/23419

[OpenStack Infra (hudson-openstack)]

Reviewed: https://review.openstack.org/23315
Committed: http://github.com/openstack/nova/commit/5f3fa391ed499750ad68ad5b000b4e2e0a86978e
Submitter: Jenkins
Branch: master

commit 5f3fa391ed499750ad68ad5b000b4e2e0a86978e
Author: Dan Smith <email address hidden>
Date: Fri Mar 1 12:44:09 2013 -0500

    Fix instance type cleanup when doing a same-id migration

    Previously, we assumed that we were moving from one flavor to another during
    a migration (i.e. a resize). That assumption failed when a regular migration
    went to delete the old_ stashed instance types from system_metadata.

    This unifies the cleanup logic, which only gets performed if we're actually
    doing a resize.

    Fixes bug 1136768

    Change-Id: I0796864b044fc746583164e4a684f79dc431c137