I have a solution. At least it works for me. Be aware that this is Devstack, but I think nothing I did to solve my problem is Devstack-specific. Also, I don't know whether there are more efficient or canonical ways to reconfigure Ceilometer. But it's good enough for me.

• in pipeline.yaml, set publisher to gnocchi://
• in the resource definition file, define my new archive policy.
  By default, this file resides in the Ceilometer source tree .../ceilometer/publisher/data/gnocchi_resources.yaml, but you can use config parameter resources_definition_file to change the default (I didn't try).
  Example:

        - name: ceilometer-medium-rate
          aggregation_methods:
          - mean
          - rate:mean
         back_window: 0
         definition:
           - granularity: 1 minute
             timespan: 7 days
           - granularity: 1 hour
             timespan: 365 days

• in the same resource definition file, adjust the archive policy of rate metrics.
  Example:

• delete all existing metrics and resources from Gnocchi
  Probably only necessary when Ceilometer is running, and not needed if you reconfigure it before its first start.
  This is a drastic measure, but if you do it at the beginning of a deployment, it won't cause loss of much data.
  Why is this required? A metric contains an archive policy that can't be changed. Thus existing metrics need to be recreated.
  Why remove resources? Because they reference the metrics that I removed.
  

• restart all Ceilometer services
  This is required for re-reading the pipeline and the resource definition files.
  Ceilometer will create resources and metrics as needed when it sends its samples to Gnocchi.

I tested this by running a CPU hogging instance and listing its measures after a few minutes:

    gnocchi measures show --resource f28f6b78-9dd5-49cc-a6ac-28cb14477bf0
                          --aggregation rate:mean cpu

    +---------------------------+-------------+---------------+
    | timestamp                 | granularity |         value |
    +---------------------------+-------------+---------------+
    | 2019-08-01T20:23:00+09:00 |        60.0 |  1810000000.0 |
    | 2019-08-01T20:24:00+09:00 |        60.0 | 39940000000.0 |
    | 2019-08-01T20:25:00+09:00 |        60.0 | 40110000000.0 |

This means that the instance accumulated 39940000000 nanoseconds of CPU time in the 60 seconds at
20:24:00. Note that the old cpu_util was expressed in percent, so that Aodh alarms and Heat autoscaling definitions must be adapted.

Good luck. Hire me as Ceilometer consultant if you get stuck :) 

Bernd

Hello Bernd, Hello Lingxian,

+1

You are not alone in your fruitless endeavor. Sadly, I can not come up with a solution.

We are stuck at the same point.

Maybe some day a dedicated member of the OpenStack community give the ceilometer guys a push to explain their service.

For us, also using Stein, it is in the state of "not production ready".

Cheers,

Ralf T.

---

Von: Bernd Bausch <berndbausch@gmail.com>
Gesendet: Donnerstag, 1. August 2019 03:16:25
An: Lingxian Kong <anlin.kong@gmail.com>
Cc: openstack-discuss <openstack-discuss@lists.openstack.org>
Betreff: Re: [telemetry][ceilometer][gnocchi] How to configure aggregate for cpu_util or calculate from metrics

 

Lingxian,

Thanks for "bumping" my request and keeping it alive. The reason I need an answer: I am updating courseware to Stein that includes autoscaling based on CPU and disk I/O rates. Looks like I am "cutting edge" :)

I don't think the problem is in the Gnocchi camp, but rather Ceilometer. To store rates of measures in z, the following is needed:

• A metric. Raw measures are sent to the metric.
  
• An archive policy. The metric has an archive policy.
  
• The archive policy includes one or more rate aggregates

My cloud has archive policies with rate aggregates, but the question is about the first bullet: How can I configure Ceilometer so that it creates the corresponding metrics and sends measures to them. In other words, how is Ceilometer's output connected to my archive policy. From my experience, just adding the archive policy to Ceilometer's publishers is not sufficient.

Ceilometer's source code includes .../publisher/data/gnocchi_resources.yaml, which might well be the place where this can be configured. I am not sure how to do it though, and this file is not documented. I can read the source, but my developer skills are insufficient for understanding how everything fits together.

Bernd

On 8/1/2019 9:01 AM, Lingxian Kong wrote:

Hi Bernd,

There were a lot of people asked the same question before, unfortunately, I don't know the answer either(we are still using an old version of Ceilometer). The original cpu_util support has been removed from Ceilometer in favor of Gnocchi, but AFAIK, there is no doc in Gnocchi mentioned how to achieve the same thing and no clear answer from the Gnocchi maintainers.

It'd be much appreciated if you could find the answer in the end, or there will be someone who has the already solved the issue.

Best regards,
Lingxian Kong

Catalyst Cloud

On Wed, Jul 31, 2019 at 1:28 PM Bernd Bausch <berndbausch@gmail.com> wrote:

The message at the end of this email is some three months old. I have the same problem. The question is: How to use the new rate metrics in Gnocchi. I am using a Stein Devstack for my tests.

For example, I need the CPU rate, formerly named cpu_util. I created a new archive policy that uses rate:mean aggregation and has a 1 minute granularity:

$ gnocchi archive-policy show ceilometer-medium-rate
+---------------------+------------------------------------------------------------------+
| Field               | Value                                                            |
+---------------------+------------------------------------------------------------------+
| aggregation_methods | rate:mean, mean                                                  |
| back_window         | 0                                                                |
| definition          | - points: 10080, granularity: 0:01:00, timespan: 7 days, 0:00:00 |
| name                | ceilometer-medium-rate                                           |
+---------------------+------------------------------------------------------------------+

I added the new policy to the publishers in pipeline.yaml:

$ tail -n5 /etc/ceilometer/pipeline.yaml
sinks:
    - name: meter_sink
      publishers:
          - gnocchi://?archive_policy=medium&filter_project=gnocchi_swift
          - gnocchi://?archive_policy=ceilometer-medium-rate&filter_project=gnocchi_swift

After restarting all of Ceilometer, my hope was that the CPU rate would magically appear in the metric list. But no: All metrics are linked to archive policy medium, and looking at the details of an instance, I don't detect anything rate-related:

$ gnocchi resource show ae3659d6-8998-44ae-a494-5248adbebe11
+-----------------------+---------------------------------------------------------------------+
| Field                 | Value                                                               |
+-----------------------+---------------------------------------------------------------------+
...
| metrics               | compute.instance.booting.time: 76fac1f5-962e-4ff2-8790-1f497c99c17d |
|                       | cpu: af930d9a-a218-4230-b729-fee7e3796944                           |
|                       | disk.ephemeral.size: 0e838da3-f78f-46bf-aefb-aeddf5ff3a80           |
|                       | disk.root.size: 5b971bbf-e0de-4e23-ba50-a4a9bf7dfe6e                |
|                       | memory.resident: 09efd98d-c848-4379-ad89-f46ec526c183               |
|                       | memory.swap.in: 1bb4bb3c-e40a-4810-997a-295b2fe2d5eb                |
|                       | memory.swap.out: 4d012697-1d89-4794-af29-61c01c925bb4               |
|                       | memory.usage: 93eab625-0def-4780-9310-eceff46aab7b                  |
|                       | memory: ea8f2152-09bd-4aac-bea5-fa8d4e72bbb1                        |
|                       | vcpus: e1c5acaf-1b10-4d34-98b5-3ad16de57a98                         |
| original_resource_id  | ae3659d6-8998-44ae-a494-5248adbebe11                                |
...

| type                  | instance                                                            |
| user_id               | a9c935f52e5540fc9befae7f91b4b3ae                                    |
+-----------------------+---------------------------------------------------------------------+

Obviously, I am missing something. Where is the missing link? What do I have to do to get CPU usage rates? Do I have to create metrics? Do I have to ask Ceilometer to create metrics? How?

Right now, no instructions seem to exist at all. If that is correct, I would be happy to write documentation once I understand how it works.

Thanks a lot.

Bernd

On 5/10/2019 3:49 PM, info@dantalion.nl wrote:

Hello,

I am working on Watcher and we are currently changing how metrics are
retrieved from different datasources such as Monasca or Gnocchi. Because
of this major overhaul I would like to validate that everything is
working correctly.

Almost all of the optimization strategies in Watcher require the cpu
utilization of an instance as metric but with newer versions of
Ceilometer this has become unavailable.

On IRC I received the information that Gnocchi could be used to
configure an aggregate and this aggregate would then report cpu
utilization, however, I have been unable to find documentation on how to
achieve this.

I was also notified that cpu_util is something that could be computed
from other metrics. When reading
https://docs.openstack.org/ceilometer/rocky/admin/telemetry-measurements.html#openstack-compute
the documentation seems to agree on this as it states that cpu_util is
measured by using a 'rate of change' transformer. But I have not been
able to find how this can be computed.

I was hoping someone could spare the time to provide documentation or
information on how this currently is best achieved.

Kind Regards,
Corne Lukken (Dantali0n)