[openstack-dev] [ceilometer] Counter relationship
yunhong.jiang at intel.com
Tue Jan 8 07:59:17 UTC 2013
> There are two type potential relationship between counters.
> One is counters from the same pollster, another one is counters from different
> pollsters. I don't think we need consider counters from notification event (am I
> We will want all of the data published by ceilometer to be processed in the
> same way, so the notification data will need to go through the pipelines, too.
I mean we don't need consider relationship from different notifications, sorry for not clear.
> Aggregation of data between counters is an implementation detail of the
> transformer or publisher that needs the aggregation, so I don't think we want
> to handle it by grouping data in our main loop. For one thing, we can't predict
> all of the ways the different transformers will want to aggregate data (by
> instance, by project, by something like the public IP address of a load balanced
> service, etc.). A more general solution would be to give the pipeline a signal
> that there is no more data coming -- a flush() call, or something similar -- and
> let the transformer handle caching data internally until it sees the end of the
For this NetPollster specific issue, I'd take Eglyn's suggestion to calculate it in the source pollster.
Generally, I think we can add or something like notification() or flulsh() to the pipeline interface in future. The notification can be information like instance closed with instance_id, IP address released etc. The pipeline pass such information down to the transformers. By default, the transformer will simply ignore such information.
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