Comment 51 for bug 1246201

Reviewed: https://review.openstack.org/188444
Committed: https://git.openstack.org/cgit/openstack/nova/commit/?id=8876294fe67048fc8cea0c3e0f5094e30c9f2c36
Submitter: Jenkins
Branch: stable/icehouse

commit 8876294fe67048fc8cea0c3e0f5094e30c9f2c36
Author: Matt Symonds <email address hidden>
Date: Wed Nov 12 01:42:37 2014 -0800

    libvirt: partial fix for live-migration with config drive

    In current version of nova, live-migration with config drive on
    local disk is forbidden due to the bug of libvirt of copying readonly
    disk. However, if we use vfat as the format of config drive,
    the function of live-migration works well.

    In this patch, we re-open the function of live-migration to admin users.
    Notice you should add 'config_drive_format=vfat' in nova.conf explicitly.

    This patch doesn't solve the problem fundamentally which need further
    efforts, but offers a simple and feasible workaround to user.

    DocImpact

    Conflicts:
            nova/virt/libvirt/driver.py

    NOTE(symonds): The conflicts are due to:
            not using is_shared_instance_path or is_shared_block_storage in stable/icehouse.

    Conflicts:
            nova/tests/unit/virt/libvirt/test_driver.py

    NOTE(symonds): The conflicts are due to:
            libvirt_driver.LibvirtDriver().pre_live_migration() returning None on success
                instead of Spice and VNC information.
            not using is_shared_instance_path or is_shared_block_storage in stable/icehouse.

    Co-Authored-By: Davanum Srinivas <email address hidden>, Matt Riedemann <email address hidden>
    Change-Id: I7429e12766da7f7f8d484b3a9df6247e832816b0
    Partial-Bug: #1246201
    (cherry picked from commit 7c4be65733e48dcf44bc306ab964fafb71b37774)