openstack team mailing list archive

[Eoghan Glynn <eglynn@xxxxxxxxxx>]

> We're running a system with a really wide variety of node types. This
> variety (nodes with 24GB, 48GB, GPU nodes, and 1TB mem nodes) causes
> some real trouble with quotas. Basically, for any tenant that is going
> to use the large memory nodes (even in smaller slices), we need to set
> quotas that are high enough that they are useless when it comes to all
> other instance types. Also, instances aren't comparable across our
> range of hardware either.
> 
> Is there a clever solution to this problem that I'm missing? Is
> anyone
> else running into this sort of properly operationally? I'm a little
> bit worried that a slightly too simple notion of quotas has been baked
> into openstack at a fairly deep level.
> thanks for any insight..

Hi Narayan,

I had the idea previously of applying a "weighting function" to the
resource usage being allocated from the quota, as opposed to simply
counting raw instances.

The notion I had in mind was more related to image usage in glance,
where the image "footprint" can vary very widely. However I think it
could be useful for some nova resources also.

Now for some resource types, for example say volumes, usage can be
controlled along multiple axes (i.e. number of volumes and total size),
so that gives more flexibility.

But if I'm hearing you correctly, you'd want to apply a lower weighting
to instances that are scheduled onto one of the higher-memory compute
nodes, and vice versa a higher weighting to instances that happen to
be run on lower-memory nodes.

Does that sum it up, or have I misunderstood?

BTW what kind of nova-scheduler config are you using?

Cheers,
Eoghan