Open Stack

Hi folks!

Just one other thing I'd like to bring up here as well:


On Thu, Feb 27, 2014 at 4:00 AM, Eugene Nikanorov
<enikanorov at mirantis.com>wrote:

> I see IP address sharing as user intent, not an implementation detail.
>> Same backend could be not only the only obstacle here.
>>
>> The backend is not exposed anyhow by the API, by the way.
>>
>> When you create root object with flavor - you really can't control to
>> which driver it will be scheduled.
>>
>> So even if there is driver that is somehow (how?) will allow same IP on
>> different backends, user just will not be able to create 2 vips that share
>> IP address.
>>
>>
>>
>> Eugene, is your point that the logical model addresses the capability for
>> IP sharing but that it can’t be scheduled correctly?
>>
> That's one of concerns, correct.
>
>>
>>
I also want to point out that there is the practical limitation that in no
IP network that I'm aware of, you can't have to different devices share the
same IP on the same layer-2 network and have this work. (I understand that
two neutron ports connected to the same netutron_network or subnet is
effectively putting them on the same layer-2 network.)  I know that an
active-standby topology can work here, but in this case we're talking about
two different VIPs sharing the same IP, not on the same device, and both
being active at the same time.  But... I've been wrong before and I just
might not be aware of any technology which makes this work:  Do any of
y'all know of any technology here which makes this feasible?

If not, then y'all must concede that this is one technological limitation
which is going to make it necessary for the user to actually specify
somehow that services collocated on the same IP must be collocated on the
same back-end (if a layer-2 topology is used).

It is possible to have two devices share the same IP in a layer-3 network
topology, but then there needs to also be some kind of logic there to
determine how packets get routed to each device (and this can break
stateful protocols like TCP if you're not careful)--  but again, this would
be "routed mode" load balancing, which I understand is not yet feasible
with Neutron LBaaS, correct?

Stephen

-- 
Stephen Balukoff
Blue Box Group, LLC
(800)613-4305 x807
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.openstack.org/pipermail/openstack-dev/attachments/20140228/a5499c4b/attachment.html>