[openstack-dev] Quantum awareness to VM live migration event

Gary Kotton gkotton at redhat.com
Wed Oct 31 08:29:14 UTC 2012


On 10/30/2012 11:26 PM, Sasha Ratkovic wrote:
> Dan,
>
> This is an example of use of "endpoint" abstraction (with attribute "host" for example). Issuing a "PUT" on this attribute would indicate VM motion (request) and request for port reassignment (quantum response).

Hi,
At the moment the port management is done as follows:
1. Nova - When Nova launches a VM it sets the "Device owner" on the port 
to "compute:nova".
2. Quantum - the plugin is responsible for setting the "status" of the 
port. In the open source plugins this is done when the the agent detects 
that the port is actually up and running.
The case of live migration is interesting. The agent is not aware, and 
in my opinion does not need to be aware, of the fact that the VM is 
being moved from one host to another. The plugin is responsible for 
updating status. At the moment there may be a race with the updating of 
the "status". The logic of the "status" management needs to be treated 
correctly by the plugin.
Does Quantum need to be aware of the host that the port is running on? I 
am not sure and have to be convinced.
Is this a bug? Yes, but only for the linux bridge plugin. I personally 
think that it needs to be addressed on a per plugin basis. I will be 
happy to look into it and address it.
Thanks
Gary


>
> Thanks,
> Sasha
>
> -----Original Message-----
> From: Dan Wendlandt [mailto:dan at nicira.com]
> Sent: Tuesday, October 30, 2012 10:08 AM
> To: Salvatore Orlando
> Cc: OpenStack Development Mailing List (openstack-dev at lists.openstack.org)
> Subject: Re: [openstack-dev] Quantum awareness to VM live migration event
>
> On Tue, Oct 30, 2012 at 2:28 AM, Salvatore Orlando<sorlando at nicira.com>  wrote:
>> Hi Irena,
>>
>> I do apologise for not having been more clear.
>> I was wondering if you are planning to extend the Quantum API, besides
>> the module that interfaces nova to quantum, in order to accomodate
>> migration events.
>> At a first glance, I believe this process could be entirely managed
>> using the existing Quantum API, but I have not explored the problem in
>> detail, so I might be missing something.
>>
>> Salvatore
> At the summit, we talked about adding calls to the Quantum admin API for a service to tell Quantum what host a particular port is being placed on (or removed from).  This helps solve some of the vif-plugging issues gary was talking about, but could also be seen as a mechanism by which nova could indicate that a port have been removed from one host, and placed on another as a result of a VM migration.
>
> dan
>
>
>>
>> On 30 October 2012 09:20, Irena Berezovsky<irenab at mellanox.com>  wrote:
>>> Moving the ongoing discussion to the openstack-dev mailing list
>>>
>>>
>>>
>>> Salvatore,
>>>
>>> Thank you for comments.
>>>
>>> I would like to add additional methods to quantum API corresponding
>>> the VM migration methods defined at nova/network/api.
>>>
>>> I am not sure what do you mean by server side calls to quantum.
>>>
>>> Just to be sure how to proceed, shall we create the blueprint for
>>> this task?
>>>
>>>
>>>
>>> Regards,
>>>
>>> Irena
>>>
>>>
>>>
>>> On 30 October 2012 08:16, Salvatore Orlando<sorlando at nicira.com>  wrote:
>>>
>>> Hi Irena,
>>>
>>>
>>>
>>> I am afraid you're correct. VM migration events were not addressed in
>>> the nova-quantum api for Folsom.
>>>
>>> We definitely want to add those calls - and help would be extremely
>>> appreciated.
>>>
>>>
>>>
>>> I think the nova-to-quantum API was mostly implemented by Yong - with
>>> some contribution from Dan, me, and other Quantum devs.
>>>
>>>
>>>
>>> Are you planning to add also server-side calls to Quantum for
>>> migration awareness?
>>>
>>>
>>>
>>> Salvatore
>>>
>>>
>>>
>>>
>>>
>>> On 30 October 2012 08:13, Irena Berezovsky<irenab at mellanox.com>  wrote:
>>>
>>> Hi guys,
>>> I have troubles to follow the flow of events in case of VMlive migration.
>>> Can I ask  you for clarifications?
>>> What I see from the code is that there is no additions to  Quantum
>>> API for migration awareness.
>>> At
>>> https://github.com/openstack/nova/blob/master/nova/network/quantumv2/
>>> api.py
>>> there is just empty implementation.
>>> Is there an intension to add Quantum API calls for live migration? Is
>>> it only nova related actions? Is some help needed?
>>>
>>> I am looking for a way to be aware of live migration at quantum
>>> plugin (due to the need to configure physical server that attached to
>>> the host that hosts VM).
>>> Thanks a lot,
>>> Irena
>>>
>>>
>>>
>>> -----Original Message-----
>>> From: Gary Kotton [mailto:gkotton at redhat.com]
>>> Sent: Sunday, October 28, 2012 10:34 AM
>>> To: Irena Berezovsky
>>>
>>> Cc: Dan Wendlandt; Salvatore Orlando
>>> Subject: Re: Quantum awareness to VM live migration event
>>>
>>> On 10/28/2012 10:27 AM, Irena Berezovsky wrote:
>>>> Hi Dan,
>>>> Thank you very much for your response.
>>>> Salvatore, Gary may I ask few questions regarding this  change?
>>>> 1. Is there some blueprint covering support for VM migration calls
>>>> to quantum API (data passed by nova) and DB model changes (if any)?
>>> Not that I am aware of
>>>> 2. Is there some description of VM migration  flow from nova
>>>> perspective?
>>> Ditto
>>>> 3. Is it part of Folsom release?
>>> Yes, this should be supported and working.
>>>> 4. Does it handle case when VM Migration fails?
>>> I would hope so.
>>>> 5. As far as I understand,  in migrate_instance_finish there is a
>>>> 'dest ' attribute. I believe its destination Physical host UUID. In
>>>> migrate_instance_start there is a 'host' attribute. Is it source
>>>> Physical Host UUID?
>>> I am not familiar with this.
>>>> Thank you in advance,
>>>> Irena
>>>>
>>>>
>>>> -----Original Message-----
>>>> From: Dan Wendlandt [mailto:dan at nicira.com]
>>>> Sent: Saturday, October 27, 2012 2:46 AM
>>>> To: Irena Berezovsky
>>>> Cc: Salvatore Orlando; Gary Kotton
>>>> Subject: Re: Quantum awareness to VM live migration event
>>>>
>>>> Hi Irena,
>>>>
>>>> Sorry, just now starting to catch up on email post-summit.
>>>>
>>>> I'm CC'ing Salvatore and Gary, as they are also involved in this, I
>>>> believe.
>>>>
>>>> Salvatore was involved with discussions with Vish and the Nova team
>>>> around the addition of migration hooks to the network api within
>>>> nova,
>>>> see:
>>>> https://github.com/openstack/nova/blob/master/nova/network/api.py#L
>>>> 337
>>>>
>>>> Gary's talk on the summit also touches on this, and would likely
>>>> add the admin calls to the Quantum API that indicate that a port is
>>>> about to be provisioned on a particular physical host (this would
>>>> probably be sent to quantum from nova when a VM is started/stopped, or migrated.
>>>>
>>>> Dan
>>>>
>>>>
>>>>
>>>>
>>>> On Mon, Oct 15, 2012 at 11:01 AM, Irena
>>>> Berezovsky<irenab at mellanox.com>
>>>> wrote:
>>>>> Dan,
>>>>> Continuing our talk today, please let me know if there is some
>>>>> work about Quantum awareness to VM live migration event (before
>>>>> and after on source and destination nodes).
>>>>>
>>>>> I would lie to be part of it,
>>>>>
>>>>> Thanks,
>>>>> Irena
>>>>
>>>> --
>>>> ~~~~~~~~~~~~~~~~~~~~~~~~~~~
>>>> Dan Wendlandt
>>>> Nicira, Inc: www.nicira.com
>>>> twitter: danwendlandt
>>>> ~~~~~~~~~~~~~~~~~~~~~~~~~~~
>>>
>>>
>>>
>>
>
>
> --
> ~~~~~~~~~~~~~~~~~~~~~~~~~~~
> Dan Wendlandt
> Nicira, Inc: www.nicira.com
> twitter: danwendlandt
> ~~~~~~~~~~~~~~~~~~~~~~~~~~~
>
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