Open Stack

On 04/28/2014 06:58 AM, Steve Gordon wrote:
> ----- Original Message -----

>> Create two new options to nova boot:
>>
>> --near-tag <TAG> and --not-near-tag <TAG>
>>
>> The first would tell the scheduler to place the new VM near other
>> VMs having a particular "tag". The latter would tell the scheduler
>> to place the new VM *not* near other VMs with a particular tag.

> Would we continue to grow this set of arguments in response to the
> addition of new policies, how much do we expect this to grow? The two
> most likely additions I can think of are "soft"/"best effort"
> versions of the current two, are there any other proposals/ideas out
> there - I know we're a creative bunch ;)?

One logical extension that came up previously is a max group size, maybe 
expressed as a quota or something.


>> 1. There's no need to have any "server group" object any more.
>> Servers have a set of tags (key/value pairs in v2/v3 API) that may
>> be used to identify a type of server. The activity of launching an
>> instance would now have options for the user to indicate their
>> affinity preference, which removes the cognitive dissonance that
>> happens due to the user needing to know what a server group is (a
>> policy, not a group).

> Would the user's affinity preference stay with the instance for
> consideration in future operations post-boot (either now or in a
> future extension of this functionality)?

Whichever way it's implemented, we need to preserve the boot time 
scheduler constraints so that any time we reschedule (migration, 
evacuation, resize, etc.) the constraints will be re-evaluated.

Chris