[Bug 1374622] [NEW] Support migration from 12.04

[Serge Hallyn]

Public bug reported:

Bug 1291321 shows that qemu VMs cannot be migrated from a host running
12.04 to a host running 14.04.

https://wiki.ubuntu.com/QemuPTMigration explains the proposed solution.

One part of the problem is that libvirt in trusty cannot distinguish a
pc-1.0 machine being migrated from 12.04 from a pc-1.0 being migrated
from 14.04.  libvirt needs a flag to tell it which to use when a pc-1.0
VM is migrated to it.  This only needs to be done for Trusty.  Any VM
running on precise can be migrated to trusty with this flag set, which
will change the machine type to pc-1.0-precise.  From there on it can be
migrated to utopic and beyond with no special casing in libvirt.

Note this depends on bugs 1374612 and 1374617, to define the machine
type and provide the binary roms which are needed for the pc-1.0-precise
machine type to be usable by libvirt.

=============================================================================
SRU Justification

Impact: VM scannot be migrated from precise to trusty
Test case: set up libvirt on a precise and a trusty host;
	add a root ssh key on the precise host and place it in the authorized_hosts file for root on the tursty host;
	restart  libvirt on the trusty host.
	start a pc-1.0 vm on precise
	migrate the vm, i.e.:
		virsh migrate --live --p2p --tunnelled --copy-storage-all vm1 qemu+ssh://trusty-host-ip/system
	This should fail.  Now edit /etc/libvirt/qemu.conf on the trusty host and add:
		assume_incoming_qemukvm = 1
	restart libvirt.  Retry migration, should now work.
Regression potential: this should change nothing if the new assume_incoming_qemukvm is not set.
=============================================================================

** Affects: libvirt (Ubuntu)
     Importance: High
         Status: Won't Fix

** Affects: libvirt (Ubuntu Trusty)
     Importance: High
         Status: New

** Also affects: libvirt (Ubuntu Trusty)
   Importance: Undecided
       Status: New

** Changed in: libvirt (Ubuntu)
       Status: New => Won't Fix

** Changed in: libvirt (Ubuntu Trusty)
   Importance: Undecided => High

** Changed in: libvirt (Ubuntu)
   Importance: Undecided => High

-- 
You received this bug notification because you are a member of Ubuntu
Server Team, which is subscribed to libvirt in Ubuntu.
https://bugs.launchpad.net/bugs/1374622

Title:
  Support migration from 12.04

To manage notifications about this bug go to:
https://bugs.launchpad.net/ubuntu/+source/libvirt/+bug/1374622/+subscriptions