ovirt-quantum integration

[Gary Kotton]

On 11/27/2012 05:06 PM, Dan Kenigsberg wrote:
> On Tue, Nov 27, 2012 at 04:43:52PM +0200, Gary Kotton wrote:
>> On 11/27/2012 04:38 PM, Dan Kenigsberg wrote:
>>> On Tue, Nov 27, 2012 at 09:06:14AM -0500, Mike Kolesnik wrote:
>>>
>>>>> ix. I do not udnerstand the race when the VM starts. There is none.
>>>>> When
>>>>> a VM starts it will send a DHCP request. If it does not receive one
>>>>> it
>>>>> will send another after a timeout. Can you please explain the race?
>>>> This is exactly it, the VM might start requesting DHCP lease before it was updated in the DHCP server, for us it's a race.
>>> I think the point is that a guest dhclient may give up before Quantum
>>> allocates it an IP. Maybe, due to timing and guests' behavior, the race
>>> would not show up, but it is still there.
>> Yes, this is certainly something that can happen if there are
>> networking problems or if something in the system is broken. How is
>> it done today in oVirt? Does someone has to go and manually update
>> the DHCP server?
> It's not done in oVirt, we want to gain it from Quantum...
> Now you'd have to log into the guest and re-initiate dhclient (or
> restart the guest) after manually configuring the DHCP server.

Quantum is certainly not perfect. It has a number of shortcomings but it 
does work. There are a number of major cloud providers that are using it 
and I do not recall them mentioning that they had problems with the 
timeout for the DHCP requests.

My two cents is that oVirt has a to gain by using Quantum. Quantum is 
moving fast - at the moment there is a lot of work being done with the 
addition of LBaaS. This is currently aimed at the end of the current 
release cycle.

This is a game changer for oVirt.

>
>> If the messaging is a real concern then you can piggyback to DHCP
>> information on the RPC call to VDSM where the DHCP agent will be
>> running. This will ensure that the information exists in the host
>> file prior to running the VM.