[Openstack-operators] [ceilometer] what is cpu_util: directly measured or derived?

gordon chung gord at live.ca
Fri Nov 18 14:48:42 UTC 2016


hi,

if you're using libvirt driver than it's derived. i assume the 
CPUUtilPollster you're referencing is the instance pollster[1] and not 
the node pollster[2]. this pollster is used by other hypervisor polling. 
there was a patch for libvirt driver to use libvirt native functionality 
to retrieve cpu_util info rather than computing it[3]. unfortunately, at 
the time, the functionality was in a version too new to match with Nova 
libvirt requirements.

ideally, Nova will bump requirements to support libvirt >= 1.3.2 (i 
don't know current status) and we won't have to compute cpu_util at all.

[1] 
https://github.com/openstack/ceilometer/blob/master/ceilometer/compute/pollsters/cpu.py#L68
[2] 
https://github.com/openstack/ceilometer/blob/master/ceilometer/ipmi/pollsters/node.py#L155
[3] https://review.openstack.org/#/c/182057/

On 17/11/16 06:55 PM, Danek Duvall wrote:
> There seem to be two different notions of cpu_util.  One is the thing
> computed by the rate_of_change transformer in the cpu_sink sink defined in
> pipeline.yaml, and the other is a direct measurement by the CPUUtilPollster.
> The latter is masked by the former, as far as I can tell, though changing
> the name in pipeline.yaml to something clever like cpu_util2 then seems to
> allow both to be presented.
>
> The telemetry-measurements page in the admin guide talk about cpu_util as
> being introduced in various releases for different hypervisors as a
> pollster-originated measurement), but then talking about cpu_util as being
> something generated by a transformer, too.
>
> Is this an oversight, or simply something left to operators to discover and
> choose between?
>
> Thanks,
> Danek
>
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>

cheers,
-- 
gord



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