openstack team mailing list archive

[Doug Hellmann <doug.hellmann@xxxxxxxxxxxxx>]

On Thu, Jun 28, 2012 at 7:52 AM, Julien Danjou <julien@xxxxxxxxxxx> wrote:

> On Thu, Jun 28 2012, Doug Hellmann wrote:
>
> > I propose that we move the code that connects to libvirt and gets the
> list
> > of instances into the class that calls the pollsters (AgentManager) so we
> > can support both calling patterns. That will make the AgentManager the
> > ComputeAgentManager (since network pollsters won't necessarily need to
> talk
> > to libvirt) and we will need other managers for calling pollsters that do
> > not use compute resources. I don't see that as a problem, since those
> > pollsters probably won't run on the compute nodes anyway so we will want
> > them to be loaded in another agent process.
> >
> > What do the rest of you think about this change?
>
> That recalls me my first idea of having one nova.service.Service (but
> only one agent daemon) by OS component. Except this time we would put
> them in only one daemon. So that sounds fine to me.
>

I'm not sure about using one daemon. It could work in some cases, but may
not scale. If we rename bin/ceilometer-agent to
bin/ceilometer-compute-agent and we add a bin/ceilometer-central-agent then
that central agent could poll a bunch of services. If we have a lot of data
to work with, though, we might want a bin/ceilometer-volume-agent and
bin/ceilometer-network-agent so those daemons can poll the separate
services more quickly. We could probably do that by making
bin/ceilometer-central-agent take a command line argument to control which
plugin(s) it loads.


> How do you propose we configure the enabled manager then? Using the same
> kind of system that we have for plugins?
>

I'm not sure we need that many different managers. If we only need a
couple, we could just have separate wrapper scripts like we do for the
collector and agent now.


> That'd basically makes us have a 2 levels plugin system in the end,
> which doesn't bother me anyway since for now everything is automagically
> configured and running.


Right.

Doug