Open Stack

There wasn't a blueprint, but you can see the change here:

https://review.openstack.org/#/c/7542/

Bandwidth is updated in a DB table outside of notifications.  Notifications just pulls the last data received and sends it.  With rapid state changes, I would expect that bandidth_usage would mostly not be different in the messages… unless a bandwidth update in the background happens to sneak in during the middle of the events.

In any case… these state change events are noted by 'compute.instance.update'.  For actions like 'rebuild', you'll get an 'exists' message when the action starts… but then you'll also see some instance.update events as the states switch.

At least this is how I understand it.  Besides the code, your best resource for information about notification payloads, etc is this:

http://wiki.openstack.org/SystemUsageData

- Chris


On Jul 2, 2012, at 4:38 AM, Day, Phil wrote:

> Hi Chris,
> 
> Thanks for the pointer on the new notification on state change stuff, I'd missed that change.
> 
> Is there a blueprint or some such which describes the change ?   
> 
> In particular I'm trying to understand how the bandwidth_usage values fit in here.  It seems that during a VM creation there would normally be a number of fairly rapid state changes, so re-calculating the bandwidth_usage figures might be quiet expensive jut to log a change in task_state from say "Networking" to "Block Device Mapping".     I was kind of expecting that to be more part of the "compute.exists" messages than the update.
> 
> Do we have something that catalogues the various notification messages and their payloads ?
> 
> Thanks,
> Phil
> 
> 
> 
> -----Original Message-----
> From: Chris Behrens [mailto:cbehrens at codestud.com] 
> Sent: 02 July 2012 00:14
> To: Day, Phil
> Cc: Jay Pipes; Huang Zhiteng; openstack at lists.launchpad.net
> Subject: Re: [Openstack] Nova and asynchronous instance launching
> 
> 
> 
> On Jul 1, 2012, at 3:04 PM, "Day, Phil" <philip.day at hp.com> wrote:
> 
>> Rather than adding debug statements could we please add additional notification events (for example a notification event whenever task_state changes)
>> 
> 
> This has been in trunk for a month or maybe a little longer.
> 
> FYI
> 
> - Chris

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