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

Thomas Maddox thomas.maddox at RACKSPACE.COM
Mon Aug 5 13:45:13 UTC 2013


Yep, I'll do that this morning. Thanks!

On 8/5/13 8:40 AM, "Julien Danjou" <julien at danjou.info> wrote:

>On Mon, Aug 05 2013, Thomas Maddox wrote:
>
>> Thinking about it, the latter option seems to describe a very real
>>concern
>> going forward that didn't occur to me when I was wandering around the
>> code. Specifically regarding option 2a, if message 2 arrives at CM
>>before
>> message 1 because it ended up on a faster route, then message 1 will
>> overwrite the metadata from message 2 and we record an incorrect state.
>> Isn't the nature of network comms for messages at the application layer
>>to
>> potentially be out of order and in the case of UDP, even lost? What is
>>the
>> leftover purpose of resource-show when we can't trust its output to
>> represent the actual state of whatever resource is in question? It seems
>> that timestamps could be used to prevent overwriting of the latest state
>> by checking that the incoming notification doesn't have a timestamp less
>> than the already recorded one. I hope I'm not seeing a problem that
>> doesn't exist here or misunderstanding something. If so, please correct
>>me!
>
>No you're absolutely right. Checking the timestamp before we override
>resource metadata would be a great idea. Would you mind reporting a bug
>first, so we can schedule to fix it?
>
>-- 
>Julien Danjou
>;; Free Software hacker ; freelance consultant
>;; http://julien.danjou.info




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