Open Stack

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?

Best,
-jay