[openstack-dev] [climate] Mirantis proposal to extend Climate to support virtual resources reservation

Patrick Petit patrick.petit at bull.net
Tue Aug 13 12:23:19 UTC 2013

Hi Nikolay,
Please see comments inline.
On 8/12/13 5:28 PM, Nikolay Starodubtsev wrote:
> Hi, again!
> Partick, I’ll try to explain why do we belive in some base actions 
> like instance starting/deleting in Climate. We are thinking about the 
> following workflow (that will be quite comfortable and user friendly, 
> and now we have more than one customer who really want it):
> 1) User goes to the OpenStack dashboard and asks Heat to reserve 
> several stacks.
> 2) Heat goes to the Climate and creates all needed leases. Also Heat 
> reserves all resources for these stacks.
> 3) When time comes, user goes to the OpenStack cloud and here we think 
> he wants to see already working stacks (ideal version) or (at least) 
> already started. If no, user will have to go to the Dashboard and wake 
> up all the stacks he or she reserved. This means several actions, that 
> may be done for the user automatically, because it will be needed to 
> do them no matter what is the aim for these stacks - if user reserves 
> them, he / she needs them.
> We understand, that there are situations when these actions may be 
> done by some other system (like some hypothetical Jenkins). But if we 
> speak about users, this will be useful. We also understand that this 
> default way of behavior should be implemented in some kind of long 
> term life cycle management system (which is not Heat), but we have no 
> one in the OpenStack now. Because the best may to implement it is to 
> use Convection, that is only proposal now...
> That’s why we think that for the behavior like “user just reserves 
> resources and then does anything he / she wants to” physical leases 
> are better variant, when user may reserve several nodes and use it in 
> different ways. For the virtual reservations it will be better to 
> start / delete them as a default way (for something unusual Heat may 
> be used and modified).
Okay. So let's bootstrap it this way then. There will be two different 
ways the reservation service will deal with reservations depending on 
whether its physical or virtual. All things being equal, future will 
tell how things settle. We will focus on the physical host reservation 
side of things. It think having this contradictory debate helped to 
understand each others use cases and requirements that the initial 
design has to cope with. Francois who already submitted a bunch of code 
for review will not return from vacation until the end of August. So 
things on our side are a little on the standby until he returns but it 
might help if you could take a look at it. I suggest you start with your 
vision and we will iterate from there. Is that okay with you?

> Do you think that this workflow is useful too and if so can you 
> propose another implementation  variant for it?
> Thank you.
> On Mon, Aug 12, 2013 at 1:55 PM, Patrick Petit <patrick.petit at bull.net 
> <mailto:patrick.petit at bull.net>> wrote:
>     On 8/9/13 3:05 PM, Nikolay Starodubtsev wrote:
>>     Hello, Patrick!
>>     We have several reasons to think that for the virtual resources
>>     this possibility is interesting. If we speak about physical
>>     resources, user may use them in the different ways, that's why it
>>     is impossible to include base actions with them to the
>>     reservation service. But speaking about virtual reservations,
>>     let's imagine user wants to reserve virtual machine. He knows
>>     everything about it - its parameters, flavor and time to be
>>     leased for. Really, in this case user wants to have already
>>     working (or at least starting to work) reserved virtual machine
>>     and it would be great to include this opportunity to the
>>     reservation service.
>>     We are thinking about base actions for the virtual reservations
>>     that will be supported by Climate, like boot/delete for instance,
>>     create/delete for volume and create/delete for the stacks. The
>>     same will be with volumes, IPs, etc. As for more complicated
>>     behaviour, it may be implemented in Heat. This will make
>>     reservations simpler to use for the end users.
>>     Don't you think so?
>     Well yes and and no. It really depends upon what you put behind
>     those lease actions. The view I am trying to sustain is separation
>     of duties to keep the service simple, ubiquitous and non
>     prescriptive of a certain kind of usage pattern. In other words,
>     keep Climate for reservation of capacity (physical or virtual),
>     Heat for orchestration, and so forth. ... Consider for example the
>     case of reservation as a non technical act but rather as a
>     business enabler for wholesales activities. Don't need, and
>     probably don't want to start or stop any resource there. I do not
>     deny that there are cases where it is desirable but then how
>     reservations are used and composed together at the end of the day
>     mainly depends on exogenous factors which couldn't be anticipated
>     because they are driven by the business.
>     And so, rather than coupling reservations with wired resource
>     instantiation actions, I would rather couple them with
>     notifications that everybody can subscribe to (as opposed to the
>     Resource Manager only) which would let users decide what to do
>     with the life-cycle events. The what to do may very well be what
>     you advocate i.e. start a full stack of reserved and interwoven
>     resources, or at the other end of the spectrum, do nothing at all.
>     This approach IMO would keep things more open.
>>     P.S. Also we remember about the problem you mentioned some
>>     letters ago - how to guarantee that user will have already
>>     working and prepared host / VM / stack / etc. by the time lease
>>     actually starts, no just "lease begins and preparing process
>>     begins too". We are working on it now.
>     Yes. I think I was explicitly referring to hosts instantiation
>     also because there is no support of that in Nova API. Climate
>     should support some kind of "reservation kick-in heads-up"
>     notification whereby the provider and/or some automated
>     provisioning tools could do the heavy lifting work of bringing
>     physical hosts online before a hosts reservation lease starts. I
>     think it doesn't have to be rocket-science either. It's probably
>     sufficient to make Climate fire up a notification that say "Lease
>     starting in x seconds", x being  an offset value against T0 that
>     could be defined by the operator based on heuristics. A dedicated
>     (e.g. IPMI) module of the Resource Manager for hosts reservation
>     would subscribe as listener to those events.
>>     On Thu, Aug 8, 2013 at 8:18 PM, Patrick Petit
>>     <patrick.petit at bull.net <mailto:patrick.petit at bull.net>> wrote:
>>         Hi Nikolay,
>>         Relying on Heat for orchestration is obviously the right
>>         thing to do. But there is still something in your design
>>         approach that I am having difficulties to comprehend since
>>         the beginning. Why do you keep thinking that orchestration
>>         and reservation should be treated together? That's adding
>>         unnecessary complexity IMHO. I just don't get it. Wouldn't it
>>         be much simpler and sufficient to say that there are pools of
>>         reserved resources you create through the reservation
>>         service. Those pools could be of different types i.e. host,
>>         instance, volume, network,.., whatever if that's really
>>         needed. Those pools are identified by a unique id that you
>>         pass along when the resource is created. That's it. You know,
>>         the AWS reservation service doesn't even care about
>>         referencing a reservation when an instance is created. The
>>         association between the two just happens behind the scene.
>>         That would work in all scenarios, manual, automatic,
>>         whatever... So, why do you care so much about this in a first
>>         place?
>>         Thanks,
>>         Patrick
>>         On 8/7/13 3:35 PM, Nikolay Starodubtsev wrote:
>>>         Patrick, responding to your comments:
>>>         1) Dina mentioned "start automatically" and "start manually"
>>>         only as examples of how these politics may look like. It
>>>         doesn't seem to be a correct approach to put orchestration
>>>         functionality (that belongs to Heat) in Climate. That's why
>>>         now we can implement the basics like starting Heat stack,
>>>         and for more complex actions we may later utilize something
>>>         like Convection (Task-as-a-Service) project.
>>>         2) If we agree that Heat is the main consumer of
>>>         Reservation-as-a-Service, we can agree that lease may be
>>>         created according to one of the following scenarions (but
>>>         not multiple):
>>>         - a Heat stack (with requirements to stack's contents) as a
>>>         resource to be reserved
>>>         - some amount of physical hosts (random ones or filtered
>>>         based on certain characteristics).
>>>         - some amount of individual VMs OR Volumes OR IPs
>>>         3) Heat might be the main consumer of virtual reservations.
>>>         If not, Heat will require development efforts in order to
>>>         support:
>>>         - reservation of a stack
>>>         - waking up a reserved stack
>>>         - performing all the usual orchestration work
>>>         We will support reservation of individual instance/volume/
>>>         IP etc, but the use case with "giving user already working
>>>         group of connected VMs, volumes, networks" seems to be the
>>>         most interesting one.
>>>         As for Heat autoscaling, reservation of the maximum
>>>         instances set in the Heat template (not the minimum value)
>>>         has to be implemented in Heat. Some open questions remain
>>>         though - like updating of Heat stack when user changes the
>>>         template to support higher max number of running instances
>>>         4) As a user, I would of course want to have it already
>>>         working, running any configured hosts/stacks/etc by the time
>>>         lease starts. But in reality we can't predict how much time
>>>         the preparation process should take for every single use
>>>         case. So if you have an idea how this should be implemented,
>>>         it would be great you share your opinion.
>>>         _______________________________________________
>>>         OpenStack-dev mailing list
>>>         OpenStack-dev at lists.openstack.org  <mailto:OpenStack-dev at lists.openstack.org>
>>>         http://lists.openstack.org/cgi-bin/mailman/listinfo/openstack-dev

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