Comment 4 for bug 1160323

Reviewed: https://review.openstack.org/25419
Committed: http://github.com/openstack/nova/commit/e507094eef9a7b4a54a04faade8aa95a36fa6d93
Submitter: Jenkins
Branch: master

commit e507094eef9a7b4a54a04faade8aa95a36fa6d93
Author: Bob Ball <email address hidden>
Date: Fri Mar 22 10:23:22 2013 +0000

    Enable live block migration when using iSCSI volumes

    Fix for bug 1160323.

    DocImpact
    Depends on a version of XAPI supporting relax-xsm-sr-check.
    Currently no release versions support this, so the change at
    https://github.com/xen-org/xen-api/pull/1116 would need to be applied
    to the source to enable this. XenServer 6.2 is expected to
    support this mode, and possibly some future hotfixes for XenServer 6.1.

    It also depends on a configuration change which must be documented and added to devstack:
    * Set "relax-xsm-sr-check = true" in /etc/xapi.conf

    This commit makes the following changes:
    * Attach the SR on the destination host prior to migrate
    * Returns the SR-ref from the pre_migrate call (API change)
    * Populates the XS VDI map with the sr-ref on the destination host
    * Removes the connection to the SR from the source host post-migrate
    * Added plugin to determine if iSCSI block migration is enabled

    Associated tempest test at https://review.openstack.org/#/c/26478/

    Change-Id: I917d9cf094190d636f4b9e14f6c8e728ff85af0e
    Fixes: bug 1160323