libvirt users - Jan 2014 - Re: Canceling a live migration via virsh? (QEMU/KVM)

On 01/08/2014 07:46 AM, Scott Sullivan wrote:
> I am using QEMU/KVM, using Live Migrations like this:
> 
> virsh migrate --live ${name} qemu+ssh://${DESTINATION}/system
> 
> My question, running this command makes it hang in the foreground. Is
> there a way for this to return immediately, so I can just poll for the
> migration status?
Not at the moment, but it might be worth adding a 'migrate --detach'
flag for that purpose, then using job control commands to track progress
independently.
> Also, is there a way to _cancel_ a migration?
Hit Ctrl-C (or any other approach for sending SIGINT to virsh).
> I see
> the --timeout option, however if a given timeout is reached I would
> rather have the ability to cancel the migration than force the suspend.
> 
> I do see there is a QEMU api migrate_cancel..eg:
> 
> virsh qemu-monitor-command ${name} --pretty
'{"execute":"migrate_cancel"}'
> 
> Is that the only way to cancel a migration using libvirt?
That way is unsupported.  The supported way (and the way used by ctrl-C
during 'virsh migrate') is to call virDomainAbortJob().

-- 
Eric Blake   eblake redhat com    +1-919-301-3266
Libvirt virtualization library http://libvirt.org

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I am using QEMU/KVM, using Live Migrations like this:

virsh migrate --live ${name} qemu+ssh://${DESTINATION}/system

My question, running this command makes it hang in the foreground. Is 
there a way for this to return immediately, so I can just poll for the 
migration status? Also, is there a way to _cancel_ a migration? I see 
the --timeout option, however if a given timeout is reached I would 
rather have the ability to cancel the migration than force the suspend.

I do see there is a QEMU api migrate_cancel..eg:

virsh qemu-monitor-command ${name} --pretty
'{"execute":"migrate_cancel"}'

Is that the only way to cancel a migration using libvirt?

On 01/08/2014 09:44 AM, Eric Blake wrote:
> On 01/08/2014 07:46 AM, Scott Sullivan wrote:
>> I am using QEMU/KVM, using Live Migrations like this:
>>
>> virsh migrate --live ${name} qemu+ssh://${DESTINATION}/system
>>
>> My question, running this command makes it hang in the foreground. Is
>> there a way for this to return immediately, so I can just poll for the
>> migration status?
> Not at the moment, but it might be worth adding a 'migrate
--detach'
> flag for that purpose, then using job control commands to track progress
> independently.
>
>> Also, is there a way to _cancel_ a migration?
> Hit Ctrl-C (or any other approach for sending SIGINT to virsh).
>
>> I see
>> the --timeout option, however if a given timeout is reached I would
>> rather have the ability to cancel the migration than force the suspend.
>>
>> I do see there is a QEMU api migrate_cancel..eg:
>>
>> virsh qemu-monitor-command ${name} --pretty
'{"execute":"migrate_cancel"}'
>>
>> Is that the only way to cancel a migration using libvirt?
> That way is unsupported.  The supported way (and the way used by ctrl-C
> during 'virsh migrate') is to call virDomainAbortJob().
>
Thanks Erik, very helpful response.