Open Stack

On 08/06/2014 01:41 PM, Jay Pipes wrote:
> On 08/06/2014 01:40 AM, Tom Fifield wrote:
>> On 06/08/14 13:30, Robert Collins wrote:
>>> On 6 August 2014 17:27, Tom Fifield <tom at openstack.org> wrote:
>>>> On 06/08/14 13:24, Robert Collins wrote:
>>>
>>>>> What happened to your DB migrations then? :)
>>>>
>>>>
>>>> Sorry if I misunderstood, I thought we were talking about running VM
>>>> downtime here?
>>>
>>> While DB migrations are running things like the nova metadata service
>>> can/will misbehave - and user code within instances will be affected.
>>> Thats arguably VM downtime.
>>>
>>> OTOH you could define it more narrowly as 'VMs are not powered off' or
>>> 'VMs are not stalled for more than 2s without a time slice' etc etc -
>>> my sense is that most users are going to be particularly concerned
>>> about things for which they have to *do something* - e.g. VMs being
>>> powered off or rebooted - but having no network for a short period
>>> while vifs are replugged and the overlay network re-establishes itself
>>> would be much less concerning.
>>
>> I think you've got it there, Rob - nicely put :)
>>
>> In many cases the users I've spoken to who are looking for a live path
>> out of nova-network on to neutron are actually completely OK with some
>> "API service" downtime (metadata service is an API service by their
>> definition). A little 'glitch' in the network is also OK for many of
>> them.
>>
>> Contrast that with the original proposal in this thread ("snapshot VMs
>> in old nova-network deployment, store in Swift or something, then launch
>> VM from a snapshot in new Neutron deployment") - it is completely
>> unacceptable and is not considered a migration path for these users.
> 
> Who are these users? Can we speak with them? Would they be interested in
> participating in the documentation and migration feature process?

Yes, I'd really like to see some participation in the development of a
solution if it's an important requirement.  Until then, it feels like a
case of an open question of "what do you want".  Of course the answer is
"a pony".

-- 
Russell Bryant