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).

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

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