[openstack-dev] [ceilometer] indicating sample provenance

Chris Dent chdent at redhat.com
Thu Aug 21 08:56:22 UTC 2014

On Thu, 21 Aug 2014, Nejc Saje wrote:

> More riffing: we are moving away from per-sample specific data with Gnocchi. 
> I don't think we should store this per-sample, since the user doesn't 
> actually care about which agent the sample came from. The user cares about 
> which *resource* it came from.

I'm thinking from a debugging and auditing standpoint it is useful
to know the hops an atom of data has taken on its way to its final
destination. Under normal circumstances that info isn't needed, but
under extraordinary circumstances it could be useful.

> I could see this going into an agent's log. On each polling cycle, we could 
> log which *resources* we are responsible (not samples).

If it goes in the agent's log how do you associate a particular
sample with that log? From the sample (or resource metadata or what
have you) you can know the time window of the resource. Now you need
to go looking around all the agents to find out which one was
satisfying that resource within that time window.

If there are two agents, no big deal, if there are 2000, problem.

And besides: Consider integration testing scenarios, making the data
a bit more meaningful will make it possible to do more flexible

I appreciate that searching through endless log files is a common
task in OpenStack but that doesn't make it the best way.

Chris Dent tw:@anticdent freenode:cdent

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