[openstack-dev] [nova] volume affinity filter for nova scheduler

Russell Bryant rbryant at redhat.com
Wed Jul 10 14:39:18 UTC 2013

On 07/10/2013 08:34 AM, Robert Collins wrote:
> On 4 July 2013 03:54, Russell Bryant <rbryant at redhat.com> wrote:
>> Thanks for starting this thread.
>> I was pushing for the weight function.  It seems much more appropriate
>> for a cloud environment than the filter.  It's an optimization that is
>> always a good idea, so the weight function that works automatically
>> would be good.  It's also transparent to users.
>> Some things I don't like about the filter:
>>  - It requires specifying a scheduler hint
>>  - It's exposing a concept of co-locating volumes and instances on the
>> same host to users.  This isn't applicable for many volume backends.  As
>> a result, it's a violation of the principle where users ideally do not
>> need to know or care about deployment details.
> We'll probably need something like this for Ironic with persistent
> volumes on machines - yes its a rare case, but when it matters, it
> matters a great deal.

I believe you, but I guess I'd like to better understand how this works
to make sure what gets added actually solves your use case.  Is there
already support for Cinder managed persistent volumes that live on
baremetal nodes?

Russell Bryant

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