Open Stack

On 10/06/2015 08:11 AM, Daniel P. Berrange wrote:
> On Tue, Oct 06, 2015 at 02:54:21PM +0100, Paul Carlton wrote:
>> https://review.openstack.org/#/c/85048/ was raised to address the
>> migration of instances that are not running but people did not warm to
>> the idea of bringing a stopped/suspended instance to a paused state to
>> migrate it.  Is there any work in progress to get libvirt enhanced to
>> perform the migration of non active virtual machines?
>
> Libvirt can "migrate" the configuration of an inactive VM, but does
> not plan todo anything related to storage migration. OpenStack could
> already solve this itself by using libvirt storage pool APIs to
> copy storage volumes across, but the storage pool worked in Nova
> is stalled
>
> https://review.openstack.org/#/q/status:abandoned+project:openstack/nova+branch:master+topic:bp/use-libvirt-storage-pools,n,z

What is the libvirt API to migrate a paused/suspended VM?  Currently nova uses 
dom.managedSave(), so it doesn't know what file libvirt used to save the state. 
  Can libvirt migrate that file transparently?

I had thought we might switch to virDomainSave() and then use the cold migration 
framework, but that requires passwordless ssh.  If there's a way to get libvirt 
to handle it internally via the storage pool API then that would be better.

Chris