openstack team mailing list archive

[Loic Dachary <loic@xxxxxxxxxxxx>]

On 04/24/2012 04:45 PM, Monsyne Dragon wrote:
>
> On Apr 24, 2012, at 9:03 AM, Loic Dachary wrote:
>
>> On 04/24/2012 03:06 PM, Monsyne Dragon wrote:
>>> Yes,  we emit bandwidth (bytes in/out) on a per VIF basis from each instance The event has the somewhat generic name of 'compute.instance.exists'  and is emitted on an periodic basis, currently by a cronjob. 
>>> Currently, we only populate bandwidth data from XenServer, but if the hook is implemented for  the kvm, etc drivers, it will be picked up automatically for them as well. 
>>>
>>> Note that we could report other metrics similarly. 
>> Hi,
>>
>> Thanks for clarifying this. So you're suggesting that the metering agent should collect this data from the nova queue instead of extracting it from the system (interface, disk stats etc.) ? And for other openstack components ( as Nick Barcet suggests below ) the metering agent will have to find another way. Or do you have something else in mind ?
>
> If it's something we have access to, we should emit it in those usage events.  As far as the other components, glance is already using the same notification system.  (there was a thread awhile back about putting it into openstack.common)  It would be nice to have all of the components using it.  
>
Hi,

I don't see a section in http://wiki.openstack.org/SystemUsageData about making sure all messages related to a billable event are accounted for. I mean, for instance, what if the event that says an instance is deleted is lost ? How is the billing software supposed to cope with that ? If it checks the status of all VM on a regular basis to deal with this, how can it figure out when the missed event occured ?

It would be worth adding a short section about this in http://wiki.openstack.org/SystemUsageData . Or I can do it if you give me a hint.

Cheers
>> Cheers
>>
>> On 04/24/2012 12:17 PM, Nick Barcet wrote:
>>> On 04/23/2012 10:45 PM, Doug Hellmann wrote:
>>>> > 
>>>> > 
>>>> > On Mon, Apr 23, 2012 at 4:14 PM, Brian Schott
>>>> > <brian.schott@xxxxxxxxxxxxxxxxxx
>>>> > <mailto:brian.schott@xxxxxxxxxxxxxxxxxx>> wrote:
>>>> > 
>>>> >     Doug,
>>>> > 
>>>> >     Do we mirror the table structure of nova, etc. and add
>>>> >     created/modified columns? 
>>>> > 
>>>> > 
>>>> >     Or do we flatten into an instance event record with everything?  
>>>> > 
>>>> > 
>>>> > I lean towards flattening the data as it is recorded and making a second
>>>> > pass during the bill calculation. You need to record instance
>>>> > modifications separately from the creation, especially if the
>>>> > modification changes the billing rate. So you might have records for:
>>>> > 
>>>> > created instance, with UUID, name, size, timestamp, ownership
>>>> > information, etc.
>>>> > resized instance, with UUID, name, new size, timestamp, ownership
>>>> > information, etc.
>>>> > deleted instance, with UUID, name, size, timestamp, ownership
>>>> > information, etc.
>>>> > 
>>>> > Maybe some of those values don't need to be reported in some cases, but
>>>> > if you record a complete picture of the state of the instance then the
>>>> > code that aggregates the event records to produce billing information
>>>> > can use it to make decisions about how to record the charges.
>>>> > 
>>>> > There is also the case where an instance is still no longer running but
>>>> > nova thinks it is (or the reverse), so some sort of auditing sweep needs
>>>> > to be included (I think that's what Dough called the "farmer" but I
>>>> > don't have my notes in front of me).
>>> When I wrote [1], one of the things that I never assumed was how agents
>>> would collect their information. I imagined that the system should allow
>>> for multiple implementation of agents that would collect the same
>>> counters, assuming that 2 implementations for the same counter should
>>> never be running at once.
>>>
>>> That said, I am not sure an event based collection of what nova is
>>> notifying would satisfy the requirements I have heard from many cloud
>>> providers:
>>> - how do we ensure that event are not forged or lost in the current nova
>>> system?
>>> - how can I be sure that an instance has not simply crashed and never
>>> started?
>>> - how can I collect information which is not captured by nova events?
>>>
>>> Hence the proposal to use a dedicated event queue for billing, allowing
>>> for agents to collect and eventually validate data from different
>>> sources, including, but not necessarily limiting, collection from the
>>> nova events.
>>>
>>> Moreover, as soon as you generalize the problem to other components than
>>> just Nova (swift, glance, quantum, daas, ...) just using the nova event
>>> queue is not an option anymore.
>>>
>>> [1] http://wiki.openstack.org/EfficientMetering
>>>
>>> Nick
>>>
>>>
>>
>>> On Apr 24, 2012, at 6:20 AM, Sandy Walsh wrote:
>>>
>>>> I think we have support for this currently in some fashion, Dragon?
>>>>
>>>> -S
>>>>
>>>>
>>>>
>>>> On 04/24/2012 12:55 AM, Loic Dachary wrote:
>>>>> Metering needs to account for the "volume of data sent to external network destinations " ( i.e. n4 in http://wiki.openstack.org/EfficientMetering ) or the disk I/O etc. This kind of resource is billable.
>>>>>
>>>>> The information described at http://wiki.openstack.org/SystemUsageData will be used by metering but other data sources need to be harvested as well.
>>> --
>>> 	Monsyne M. Dragon
>>> 	OpenStack/Nova 
>>> 	cell 210-441-0965
>>> 	work x 5014190
>>>
>>>
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>>
>>
>> -- 
>> Loïc Dachary         Chief Research Officer
>> // eNovance labs   http://labs.enovance.com
>> // ✉ loic@xxxxxxxxxxxx  ☎ +33 1 49 70 99 82
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>
> --
> Monsyne M. Dragon
> OpenStack/Nova 
> cell 210-441-0965
> work x 5014190
>


-- 
Loïc Dachary         Chief Research Officer
// eNovance labs   http://labs.enovance.com
// ✉ loic@xxxxxxxxxxxx  ☎ +33 1 49 70 99 82