Open Stack

On 19/11/2019 21:55, Lingxian Kong wrote:
> On Wed, Nov 20, 2019 at 8:33 AM Matthias Runge <mrunge at matthias-runge.de
> <mailto:mrunge at matthias-runge.de>> wrote:
> 
>     tbh, I am surprised to see the telemetry team trying to roll back to
>     something, which is known to cause a lot of performance issues. There
>     were good reasons for splitting ceilometer into several components.
> 
> 
> I understand your concerns and the team will find a better way to deal
> with the rollback, the expected result is that it won't break anyone who
> are using Gnocchi or other storage backend but it means much to the
> cloud providers(like OVH and us) who are still using old version
> Ceilometer and relying on the API.


I assume, you haven't seen any performance issues with both Ceilometer
or Gnocchi?

> 
>     There were lots of good ideas and suggestions already shared in this
>     thread. My proposal here would be to keep ceilometer as is (as data
>     collecting agent) and to write missing glue to digest or send data to a
>     time-series database, like InfluxDB or Prometheus (plus many more
>     options, not mentioned here).
> 
> 
> Does InfluxDB or Prometheus support to store samples that could be
> leveraged for auditing or billing purpose? I'm not familiar with TSDB
> but I got the answer NO according to the chatting with some other
> people

Billing is a complicated beast for multiple reasons. Let's look only at
ingestion. First of all, you are right, e.g Prometheus should not be
used in billing situations, see[1], also on [2] (same source as [1]).

However, the same is true for Gnocchi and also for Ceilometer. You are
going to loose metrics if your collection is faster than your backend
can digest it, for Gnocchi is such behaviour documented. If you are
looking at speed, I'd consider prometheus to be much faster than gnocchi
and ceilometer and thus better suited for handling metrics.



[1]
https://github.com/prometheus/docs/blob/master/content/docs/introduction/overview.md#when-does-it-not-fit
[2] https://prometheus.io/docs/introduction/overview/#when-does-it-not-fit

>     If I remember correctly, MongoDB was deprecated because of the issues it
>     caused and also because it was removed from Linux distributions, since
>     there were the licensing issues.
> 
> 
> I don't think the license change will affect the cloud that only uses
> MongoDB as internal service backend storage unless I'm missing
> something.

You can read a bit of story on MongoDB relicensing at [3].

The license change was regarding commercial use. You can find the full
text at [4], depending on your use case, it may be valuable to ask a
lawyer, especially, when in doubt.



[3]
https://hub.packtpub.com/mongodb-withdraws-controversial-server-side-public-license-from-the-open-source-initiatives-approval-process/
[4] https://www.mongodb.com/licensing/server-side-public-license

>From my POV (and apparently others here in this thread as well), I'd
take a step back and revisit
https://storyboard.openstack.org/#!/board/205 again, in order to run
into the same issues as in Newton cycle. I mean, if you'd want
ceilometer from Newton, it is still there.

Matthias