Open Stack

________________________________
From: Doug Hellmann [doug.hellmann at dreamhost.com]
Sent: Thursday, November 08, 2012 1:54 PM
To: Sandy Walsh
Cc: Eoghan Glynn; OpenStack Development Mailing List; openstack at lists.launchpad.net
Subject: Re: [Openstack] [openstack-dev] [metering][ceilometer] Unified Instrumentation, Metering, Monitoring ...



On Wed, Nov 7, 2012 at 10:21 PM, Sandy Walsh <sandy.walsh at rackspace.com<mailto:sandy.walsh at rackspace.com>> wrote:
Hey!

(sorry for the top-posting, crappy web client)

There is a periodic task already in the compute manager that can handle this:
https://github.com/openstack/nova/blob/master/nova/compute/manager.py#L3021

There seems to be some recent (to me) changes in the manager now wrt the resource_tracker.py and stats.py files about how this information gets relayed. Now it seems it only goes to the db, but previously it was sent to a fanout queue that the schedulers could use.

Regardless, this is done at a high enough level that it doesn't really care about the underlying virt layer, so long at the virt layer supports the get_available_resource() method.

https://github.com/openstack/nova/blob/master/nova/compute/resource_tracker.py#L152
https://github.com/openstack/nova/blob/master/nova/virt/xenapi/driver.py#L392
https://github.com/openstack/nova/blob/master/nova/virt/libvirt/driver.py#L2209

I'd add a hook in there do what we want with this data. Write it to the db, send it over the wire, whatever. If there is additional information required, it should go in this dictionary (or we should define a format for extensions to it).

Yes

> It looks like that is collecting resource data, but not usage data. For example, there's no disk I/O information, just disk space. Is that what you mean by adding extra information to the dictionary?
>
> Doug

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