[openstack-dev] Custom Flavor creation through Heat
Kodam, Vijayakumar (EXT-Tata Consultancy Ser - FI/Espoo)
vijayakumar.kodam.ext at nsn.com
Thu Nov 14 08:53:41 UTC 2013
>not the video I was looking for, but he kind of makes the point about planning...
># Shawn Hartsock
Thanks Shawn for your inputs. As I have mentioned earlier, the usecase is mostly for telecom cloud applications running in our private cloud.
The hardware requirements for them are quite different from the usual IT hardware requirements.
We also have to use extra-specs to help nova schedule the virtual instances and to make other decisions.
And the flavors we create will be mostly visible/accessible to the tenant which creates them.
This restriction could be imposed using flavor-access feature of nova.
>>----- Original Message -----
>> From: "Shawn Hartsock" <hartsocks at vmware.com>
>> To: "OpenStack Development Mailing List (not for usage questions)" <openstack-dev at lists.openstack.org>
>> Sent: Tuesday, November 12, 2013 6:38:21 PM
>> Subject: Re: [openstack-dev] Custom Flavor creation through Heat
>> ----- Original Message -----
>> > From: "Yunhong Jiang" <yunhong.jiang at intel.com>
>> > To: "OpenStack Development Mailing List (not for usage questions)"
>> > <openstack-dev at lists.openstack.org>
>> > Sent: Tuesday, November 12, 2013 5:39:58 PM
>> > Subject: Re: [openstack-dev] Custom Flavor creation through Heat
>> > > -----Original Message-----
>> > > From: Shawn Hartsock [mailto:hartsocks at vmware.com]
>> > > Sent: Tuesday, November 12, 2013 12:56 PM
>> > > To: OpenStack Development Mailing List (not for usage questions)
>> > > Subject: Re: [openstack-dev] [nova] [heat] Custom Flavor creation through
>> > > Heat
>> > >
>> > > My concern with proliferating custom flavors is that it might play havoc
>> > > with the underlying root-case for flavors.
>> > >
>> > > My understanding of flavors is that they are used to solve the resource
>> > > packing problem in elastic cloud scenarios. That way you know that 256
>> > > "tiny" VMs fit cleanly into your hardware layout and so do 128 "medium"
>> > > VMs and 64 large VMs. If you allow "flavor of the week" then the packing
>> > > problem re-asserts itself and scheduling becomes harder.
>> > I'm a bit surprised that the flavor is used to resolve the packing problem.
>> > I
>> > thought it should be handled by scheduler, although it's a NP problem.
>> I should have said "flavors help to make the packing problem simpler for the
>> scheduler" ... flavors do not "solve" the packing problem.
>> > As for custom flavor, I think at least it's against current nova
>> > assumption.
>> > Currently nova assume flavor should only be created by admin, who knows the
>> > cloud quite well.
>> > One example is, flavor may contain extra-spec, so if an extra-spec value is
>> > specified in the flavor, while the corresponding scheduler filter is not
>> > enabled, then the extra-spec has no effect and may cause issue.
>> Beyond merely extra-specs my understanding was that because you *have*
>> flavors you can make assumptions about packing that make the problem space
>> smaller... someone made a nice presentation showing how having restricted
>> flavors made scheduling easier. I can't find it right now. It was presented
>> at an OpenStack summit IIRC.
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