[openstack-dev] More on the topic of DELIMITER, the Quota Management Library proposal

Jay Pipes jaypipes at gmail.com
Sat Apr 23 19:25:45 UTC 2016

On 04/23/2016 03:18 PM, Mike Perez wrote:
> On 14:54 Apr 18, Jay Pipes wrote:
>> On 04/16/2016 05:51 PM, Amrith Kumar wrote:
>>>          - update_resource(id or resource, newsize)
>> Resizing resources is a bad idea, IMHO. Resources are easier to deal with
>> when they are considered of immutable size and simple (i.e. not complex or
>> nested). I think the problem here is in the definition of resource classes
>> improperly.
>> For example, a "cluster" is not a resource. It is a collection of resources
>> of type node. "Resizing" a cluster is a misnomer, because you aren't
>> resizing a resource at all. Instead, you are creating or destroying
>> resources inside the cluster (i.e. joining or leaving cluster nodes).
>> BTW, this is also why the "resize instance" API in Nova is such a giant pain
>> in the ass. It's attempting to "modify" the instance "resource" when the
>> instance isn't really the resource at all. The VCPU, RAM_MB, DISK_GB, and
>> PCI devices are the actual resources. The instance is a convenient way to
>> tie those resources together, and doing a "resize" of the instance behind
>> the scenes actually performs a *move* operation, which isn't a *change* of
>> the original resources. Rather, it is a creation of a new set of resources
>> (of the new amounts) and a deletion of the old set of resources.
> How about extending a volume? A volume is a resource and can be extended in
> Cinder today.

Yep, understood :) I recognize some resource amounts can be modified for 
some resource classes. How about *shrinking* a volume. Is that supported?


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