On Wed, Dec 05, 2012 at 10:51:23PM +0200, Itamar Heim wrote:
> On 12/05/2012 10:33 PM, Adam Litke wrote:
> >On Wed, Dec 05, 2012 at 10:21:39PM +0200, Itamar Heim wrote:
> >>On 12/05/2012 10:16 PM, Adam Litke wrote:
> >>>On Wed, Dec 05, 2012 at 09:01:24PM +0200, Itamar Heim wrote:
> >>>>On 12/05/2012 08:57 PM, Adam Litke wrote:
> >>>>>On Wed, Dec 05, 2012 at 08:30:10PM +0200, Itamar Heim wrote:
> >>>>>>On 12/05/2012 04:42 PM, Adam Litke wrote:
> >>>>>>>>I wanted to know what do you think about it and if you have better
> >>>>>>>>>solution to avoid initiate so many threads? And if splitting vdsm is
> >>>>>>>>>a good idea here?
> >>>>>>>>>In first look, my opinion is that it can help and would be nice to
> >>>>>>>>>have vmStatisticService that runs and writes to separate log the vms
> >>>>>>>>>status.
> >>>>>>>Vdsm recently started requiring the MOM package.  MOM also performs 
> >>>>>>>some host
> >>>>>>>and guest statistics collection as part of the policy framework.  I 
> >>>>>>>think it
> >>>>>>>would be a really good idea to consolidate all stats collection into 
> >>>>>>>MOM.  Then,
> >>>>>>>all stats become usable within the policy and by vdsm for its own 
> >>>>>>>internal
> >>>>>>>purposes.  Today, MOM has one stats collection thread per VM and one 
> >>>>>>>thread for
> >>>>>>>the host stats.  It has an API for gathering the most recently 
> >>>>>>>collected stats
> >>>>>>>which vdsm can use.
> >>>>>>>
> >>>>>>
> >>>>>>isn't this what collectd (and its libvirt plugin) or pcp are already 
> >>>>>>doing?
> >>>>>
> >>>>>Lot's of things collect statistics, but as of right now, we're using MOM 
> >>>>>and
> >>>>>we're not yet using collectd on the host, right?
> >>>>>
> >>>>
> >>>>I think we should have a single stats collection service and clients for 
> >>>>it.
> >>>>I think mom and vdsm should get their stats from that service,
> >>>>rather than have either beholden to any new stats something needs to
> >>>>collect.
> >>>
> >>>How would this work for collecting guest statistics?  Would we require 
> >>>collectd
> >>>to be installed in all guests running under oVirt?
> >>>
> >>
> >>my understanding is collectd is installed on the host, and uses
> >>collects libvirt plugin to collect guests statistics?
> >
> >Yes, but some statistics can only be collected by making a call to the oVirt
> >guest agent (eg. guest memory statistics).  The logical next step would be to
> >write a collectd plugin for ovirt-guest-agent, but vdsm owns the connections 
> >to
> >the guest agents and probably does not want to multiplex those connections 
> >for
> >many reasons (security being the main one).
> >
> and some will come from qemu-ga which libvirt will support?
> maybe a collectd vdsm plugin for the guest agent stats?

Then you still have vdsm plus one other entitity in the business of stats
collection.  I don't see how that's any better than what we have today.

Adam Litke <a...@us.ibm.com>
IBM Linux Technology Center

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