[openstack-dev] Climate Incubation Application

Joe Gordon joe.gordon0 at gmail.com
Thu Mar 6 19:00:54 UTC 2014

On Thu, Mar 6, 2014 at 3:11 AM, Sylvain Bauza <sylvain.bauza at gmail.com> wrote:
> Hi Thierry,
> 2014-03-06 11:46 GMT+01:00 Thierry Carrez <thierry at openstack.org>:
>> Dina Belova wrote:
>> >> Would Climate also be usable to support functionality like Spot
>> >> Instances ? "Schedule when spot price falls under X" ?
>> >
>> > Really good question. Personally I think that Climate might help
>> > implementing this feature, but probably it's not the main thing that
>> > will work there.
>> >
>> > Here are my concerns about it. Spot instances require way of counting
>> > instance price:
>> > [...]
>> Not necessarily. It's a question of whether Climate would handle only
>> "schedule at" (a given date), or more generally "schedule when" (a
>> certain event happens, with date just being one event type). You can
>> depend on some external system setting spot prices, or any other
>> information, and climate rules that would watch regularly that external
>> information to decide if it's time to run resources or not. I don't
>> think it should be Climate's responsibility to specifically maintain
>> spot price, everyone can come up with their own rules.
> I can't agree more on this. The goal of Climate is to provide some formal
> contract agreement in betwen an user and the Reservation service, for
> ensuring that the order will be placed and served correctly (with regards to
> quotas and capacity). Of course, what we call 'user' doesn't formally tend
> to be a 'real' user.
> About spot instances use-case, I don't pretend to design it, but I could
> easily imagine that a call to Nova for booting an instance would place an
> order to Climate with a specific type of contract (what we began to call
> 'best-effort' and which needs to be implemented yet) where notifications for
> acquitting the order would come from Ceilometer (for instance). If no
> notifications come to Climate, the lease would not be honored.
> See https://wiki.openstack.org/wiki/Climate#Lease_types_.28concepts.29 for
> best-effort definition of a lease.

"Immediate reservation. Resources are provisioned immediately (like VM
boot or moving host to reserved user aggregate) or not at all. If
request can be fulfilled, lease is created and success status is
returned. Lease should be marked as active or to_be_started. Otherwise
(if request resource cannot be provisioned right now) failure status
for this request should be returned."

Isn't this what what nova does today? why is climate needed for this?

Also your concept of 'Best-effort reservation.' is very different from
spot instances.

Spot instances will terminate terminate when the price goes above a
threshhold, I didn't see anything like that here.

> -Sylvain
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