[openstack-dev] [nova][scheduler] Proposal: FairShareScheduler.

Lisa lisa.zangrando at pd.infn.it
Tue Jul 8 11:18:19 UTC 2014


Hi Sylvain,

On 08/07/2014 09:29, Sylvain Bauza wrote:
> Le 08/07/2014 00:35, Joe Gordon a écrit :
>>
>>
>> On Jul 7, 2014 9:50 AM, "Lisa" <lisa.zangrando at pd.infn.it 
>> <mailto:lisa.zangrando at pd.infn.it>> wrote:
>> >
>> > Hi all,
>> >
>> > during the last IRC meeting, for better understanding our proposal 
>> (i.e the FairShareScheduler), you suggested us to provide (for the 
>> tomorrow meeting) a document which fully describes our use cases. 
>> Such document is attached to this e-mail.
>> > Any comment and feedback is welcome.
>>
>> The attached document was very helpful, than you.
>>
>> It sounds like Amazon's concept of spot instances ( as a user facing 
>> abstraction) would solve your use case in its entirety. I see spot 
>> instances as the general solution to the question of how to keep a 
>> cloud at full utilization. If so then perhaps we can refocus this 
>> discussion on the best way for Openstack to support Amazon style spot 
>> instances.
>>
>
>
>
> Can't agree more. Thanks Lisa for your use-cases, really helpful for 
> understand your concerns which are really HPC-based. If we want to 
> translate what you call Type 3 in a non-HPC world where users could 
> compete for a resource, spot instances model is coming to me as a 
> clear model.

our model is similar to the Amazon's spot instances model because both 
try to maximize the resource utilization. The main difference is the 
mechanism used for assigning resources to the users (the user's offer in 
terms of money vs the user's share). They differ even on how they 
release the allocated resources. In our model, the user, whenever 
requires the creation of a Type 3 VM, she has to select one of the 
possible types of "life time" (short = 4 hours, medium = 24 hours, long 
= 48 hours). When the time expires, the VM is automatically released (if 
not explicitly released by the user).
Instead, in Amazon, the spot instance is released whenever the spot 
price rises.


>
> I can see that you mention Blazar in your paper, and I appreciate 
> this. Climate (because that's the former and better known name) has 
> been kick-off because of such a rationale that you mention : we need 
> to define a contract (call it SLA if you wish) in between the user and 
> the platform.
> And you probably missed it, because I was probably unclear when we 
> discussed, but the final goal for Climate is *not* to have a 
> start_date and an end_date, but just *provide a contract in between 
> the user and the platform* (see 
> https://wiki.openstack.org/wiki/Blazar#Lease_types_.28concepts.29 )
>
> Defining spot instances in OpenStack is a running question, each time 
> discussed when we presented Climate (now Blazar) at the Summits : what 
> is Climate? Is it something planning to provide spot instances ? Can 
> Climate provide spot instances ?
>
> I'm not saying that Climate (now Blazar) would be the only project 
> involved for managing spot instances. By looking at a draft a couple 
> of months before, I thought that this scenario would possibly involve 
> Climate for best-effort leases (see again the Lease concepts in the 
> wiki above), but also the Nova scheduler (for accounting the lease 
> requests) and probably Ceilometer (for the auditing and metering side).
>
> Blazar is now in a turn where we're missing contributors because we 
> are a Stackforge project, so we work with a minimal bandwidth and we 
> don't have time for implementing best-effort leases but maybe that's 
> something we could discuss. If you're willing to contribute to an 
> Openstack-style project, I'm personnally thinking Blazar is a good one 
> because of its little complexity as of now.
>


Just few questions. We read your use cases and it seems you had some 
issues with the quota handling. How did you solved it?
About the Blazar's architecture 
(https://wiki.openstack.org/w/images/c/cb/Climate_architecture.png): the 
resource plug-in interacts even with the nova-scheduler?
Such scheduler has been (or will be) extended for supporting the 
Blazar's requests?
Which relationship there is between nova-scheduler and Gantt?

It would be nice to discuss with you in details.
Thanks a lot for your feedback.
Cheers,
Lisa



>
> Thanks,
> -Sylvain
>
>
>
>
>
>> > Thanks a lot.
>> > Cheers,
>> > Lisa
>> >
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