pre_live_migration should not require a static IP Address

[Drew Thorstensen]

The nova/compute/manager.py - pre_live_migration method is checking to ensure that there is at least a single fixed IP Address on the instance. The comment above it indicates that this shouldn't be required (and it is not clear that it is even required). Live migrations are blocked for systems that do not have a fixed IP Address.

If a system does not have a fixed IP, then the following error is thrown:
2013-09-11 16:01:02.548 97997 TRACE nova.openstack.common.rpc.amqp File "/usr/lib/python2.6/site-packages/nova/exception.py", line 88, in wrapped
2013-09-11 16:01:02.548 97997 TRACE nova.openstack.common.rpc.amqp event_type, level, payload)
2013-09-11 16:01:02.548 97997 TRACE nova.openstack.common.rpc.amqp File "/usr/lib/python2.6/site-packages/nova/exception.py", line 76, in wrapped
2013-09-11 16:01:02.548 97997 TRACE nova.openstack.common.rpc.amqp return f(self, context, *args, **kw)
2013-09-11 16:01:02.548 97997 TRACE nova.openstack.common.rpc.amqp File "/usr/lib/python2.6/site-packages/nova/compute/manager.py", line 3850, in pre_live_migration
2013-09-11 16:01:02.548 97997 TRACE nova.openstack.common.rpc.amqp instance_uuid=instance['uuid'])
2013-09-11 16:01:02.548 97997 TRACE nova.openstack.common.rpc.amqp FixedIpNotFoundForInstance: Instance eb586597-3565-4283-88d3-d0664f4d5747 has zero fixed ips.

[OpenStack Infra (hudson-openstack)]

Fix proposed to branch: master
Review: https://review.openstack.org/47479

[OpenStack Infra (hudson-openstack)]

Reviewed: https://review.openstack.org/47479
Committed: http://github.com/openstack/nova/commit/9b88e54998f0e197a29413a28dc101c5bbb7e89e
Submitter: Jenkins
Branch: master

commit 9b88e54998f0e197a29413a28dc101c5bbb7e89e
Author: Drew Thorstensen <email address hidden>
Date: Thu Sep 19 15:49:48 2013 -0500

    Removes pre_live_migration need for Fixed IPs

    This commit removes the validation that requires Fixed IP Addresses
    for pre_live_migration. The original comment regarding the
    pre_live_migration requiring Fixed IP Addresses alluded to uncertainty
    about it not being required. Workloads should not require a Fixed IP
    Address for migration, typically just the storage is required to be
    similar.

    The commit also updates the associated test case to ensure that no
    exception is thrown in the pre_live_migration if a fixed IP Address
    is not specified.

    Change-Id: I2c4d4dae2cb0f00c67f0f731b5080196564b37da
    Closes-Bug: #1226226