[openstack-dev] [Ceilometer] Looking for some help understanding default meters

Julien Danjou julien at danjou.info
Mon Aug 5 08:14:47 UTC 2013

On Fri, Aug 02 2013, Thomas Maddox wrote:

Hi Thomas,

> I've been poking around to get an understanding of what some of these
> default meters mean in the course of researching this Glance bug
> (https://bugs.launchpad.net/ceilometer/+bug/1201701). I was wondering if
> anyone could explain to me what the instance meter is. The unit 'instance'
> sort of confuses me when each one of these meters is tied to a single
> resource (instance), especially because it looks like a count of all
> notifications regarding a particular instance that hit the bus. Here's some
> output for one of the instances I spun up:
> http://paste.openstack.org/show/42963/.

Are you talking about instance:m1.nano like counters?
These are old counters we introduce a while back to count directly the
number of instances by summing up all these counters. That's something
that should now be done via the API -- I'll look into removing them.

About the general instance counter, that's just a gauge counter which
has always value = 1, counting the number of 'instance' on a particular
resource, in this case, the instance itself. So it's just some sort of a
heartbeat counting instances.

> Another concern I have is I think I
> may have found another bug, because I can delete the instance shown in this
> paste, and it still has a resource state description of 'scheduling' long
> after it's been deleted: http://paste.openstack.org/show/42962/, much like
> the Glance issue I'm currently working on.

Then you use resource-show, Ceilometer just returns the latest metadata
it has about the resource. So this should be equal to the
resource_metadata field of the more recent samples it has in this
database (hint: you could go and check this out in the db yourself to be

Now, 2 options:
- the latest sample retrieved by Ceilometer shows differents metadata,
  so there's a bug in Ceilometer
- the latests sample retrieve by Ceilometer shows the same information,
   a. a message arrived late and out of order to Ceilometer, so the
   resource metadata is oudated -- we can't do much about it
   b. this is actually what Nova sends to Ceilometer -- much likely a
   bug in Nova.

Julien Danjou
;; Free Software hacker ; freelance consultant
;; http://julien.danjou.info
-------------- next part --------------
A non-text attachment was scrubbed...
Name: signature.asc
Type: application/pgp-signature
Size: 835 bytes
Desc: not available
URL: <http://lists.openstack.org/pipermail/openstack-dev/attachments/20130805/0f5df309/attachment.pgp>

More information about the OpenStack-dev mailing list