[Openstack] Why doesn't suspend release vCPUs/memory?

Ricky Saltzer ricky at cloudera.com
Tue Jun 24 19:58:28 UTC 2014


I don't see how there would be a problem if you still enforced a hard limit
of the number of instances a user can have. The proposal here is suspending
would release *only* vCPUs and memory, so the user could still potentially
exceed their quota by reaching their allotted amount of instances. Let's
say 5/10 instances for a user accumulated to 20 vCPUs (4 vCPUs per node),
suspending those 5 instances would release the 20 vCPUs back, but those 5
suspended instances would still count towards their total number of
instances quota.




On Mon, Jun 23, 2014 at 11:24 PM, Wangpan <hzwangpan at corp.netease.com>
wrote:

>   I think if we do this, a serious security risk is imported, think this
> use case:
> 1) an user has quotas like 10 instances, 20 vcpus, 100G ram and 200G disks
> 2) he boots 10 instances under his quotas
> 3) he suspends all this instances
> 4) he repeats step 2&3 day and night
> 5) then the cloud platform will have no resources to supply eventually
>
> 2014-06-24 11:17 (UTC+8)
> Wangpan
>
> ----- Original Message -----
> > From: Ricky Saltzer <ricky at cloudera.com>
> > To: "John Griffith"<john.griffith at solidfire.com>
> > Sent: 2014-06-24 01:05
> > Subject: Re: [Openstack] Why doesn't suspend release vCPUs/memory?
>
>  That seems to be the case, and I can see where you're coming from, but
> if the resources aren't released at the quota level, then they're
> effectively being used from a user's point of view. It would be nice if
> *suspend* released resources after the instance is shutdown, and a
> *resume* would reclaim the resources (provided enough are available). For
> instance, if I had 210/210 vCPUs used, and I suspend *instance_a* with 1
> vCPU, and then launch *instance_b *with 1 vCPU...*instance_b *should
> successfully deploy, but resuming *instance_a* should fail with a quota
> exceeded exception.
>
>
>
> On Mon, Jun 23, 2014 at 12:54 PM, John Griffith <
> john.griffith at solidfire.com> wrote:
>
>>
>>
>>
>> On Mon, Jun 23, 2014 at 10:49 AM, Ricky Saltzer <ricky at cloudera.com>
>> wrote:
>>
>>> Right, the quotas don't seem to be released. If I have 210/210 vCPUs
>>> used, and I suspend an instance with 4 vCPUs, I still have 210/210 vCPUs
>>> used.
>>>
>>>
>>> On Mon, Jun 23, 2014 at 11:38 AM, John Griffith <
>>> john.griffith at solidfire.com> wrote:
>>>
>>>>
>>>> On Mon, Jun 23, 2014 at 7:45 AM, Ricky Saltzer <ricky at cloudera.com>
>>>> wrote:
>>>>
>>>>>
>>>>> https://ask.openstack.org/en/question/32826/why-doesnt-suspend-release-vcpusmemory/
>>>>
>>>>
>>>> ​My understanding was always that the instance is no longer consuming
>>>> any resources via the virt layer, so in essence the resources are in fact
>>>> freed up on the Compute Node.  Quotas and such however aren't modified
>>>> (which seems correct to me).  Are you saying you want to see quota's
>>>> adjusted here? ​
>>>>
>>>>
>>>
>>>
>>> --
>>>  Ricky Saltzer
>>> http://www.cloudera.com
>>>
>>> ​Yeah, I think that makes sense and is expected, as a user you're still
>> consuming those "items" even if they're not active.  The alternative would
>> be (which I think is what you're getting at) to actually deduct items that
>> are suspended from the tenants quota count.  I guess when I think of it
>> though those resources are still "reserved" even if they're not in use.  I
>> suppose you could do this and then if on resume the quota isn't there we
>> don't actually resume... but I think this could be argued either way.
>>
>> Maybe seperate quotas for active vs suspended?  ​
>>
>>
>
>
> --
>  Ricky Saltzer
> http://www.cloudera.com
>
>


-- 
Ricky Saltzer
http://www.cloudera.com
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