Open Stack

On Thu, Oct 25 2012, Dan Dyer wrote:

> I don't think its just a matter of adding more meters or events for a couple
> of reasons:
> 1. In many cases the metadata I am referring to comes from a different
> source than the base usage data. Nova is still emitting its normal events,
> but we get the service/user mapping from a different source. I would not
> characterize this data as usage metrics but more data about the system
> relationships.
> 2. in the multiple VM case, we need to have the relationships specified so
> that we can ignore the proper VM's. There has also been talk of hybrid
> billing models that charge for some part of the VM usage as well as other
> metrics. Once again we need a way to characterize the relationships so that
> processing can associate and filter correctly.

Sure, I am not stating you don't need to specify the relationship. I'm
just saying I don't see why existing counter in ceilometer should be
modified to store the relationship and why it should be aware of it.

Maybe I don't understand properly what you want to do, so I'll try to
give a concrete example. Please correct me and amend the example if it
doesn't match what you've in mind.


Let's say you have a PaaS platform built on instances. This PaaS
platform has a user P in keystone and launches instances with that user.

Now you have to spawn the platform, or a new instance of it, doesn't
matter, and launch let's 3 VM instances X, Y and Z. Ceilometer records
that 3 VMs instances are running for user P the entire lifetime of the
platform.

At this point, what I'm saying is that your PaaS platform also needs to
send meters too like: "Customer C is using the platform running on VM X,
Y and Z". The VM the platform is using can be stored in the metadata of
the meter the platform emits. You don't need to modify the existing
meters.

With that, it's possible when billing customer C to request all meters
concerning the PaaS platform (you filter by counter name and/or source)
and bill the PaaS platform to C. If you want detail usage, or charge
back your platform owner, you also can bill the platform using the meter
on the VM (and here bill the IaaS part).

So the relationship is stored in Ceilometer (via metadata) and you can
exploit it to build a more complex billing system with more layers.

How does that sound?

-- 
Julien Danjou
;; Free Software hacker & freelance
;; http://julien.danjou.info
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