On Mon, Nov 18, 2013 at 9:40 AM, Doug Hellmann <doug.hellm...@dreamhost.com>wrote:
> > On Mon, Nov 18, 2013 at 12:25 PM, Devananda van der Veen < > devananda....@gmail.com> wrote: > >> Hi Lianhao Lu, >> >> I briefly summarized my recollection of that session in this blueprint: >> >> https://blueprints.launchpad.net/ironic/+spec/add-ceilometer-agent >> >> I've responded to your questions inline as well. >> >> >> On Sun, Nov 17, 2013 at 10:24 PM, Lu, Lianhao <lianhao...@intel.com>wrote: >> >>> Hi stackers, >>> >>> During the summit session Expose hardware sensor (IPMI) data >>> https://etherpad.openstack.org/p/icehouse-summit-ceilometer-hardware-sensors, >>> it was proposed to deploy a ceilometer agent next to the ironic conductor >>> to the get the ipmi data. Here I'd like to ask some questions to figure out >>> what's the current missing pieces in ironic and ceilometer for that >>> proposal. >>> >>> 1. Just double check, ironic won't provide API to get IPMI data, right? >>> >> >> Correct. This was generally felt to be unnecessary. >> >>> >>> 2. If deploying a ceilometer agent next to the ironic conductor, how >>> does the agent talk to the conductor? Through rpc? >>> >> >> My understanding is that ironic-conductor will emit messages to the >> ceilimeter agent, and the communication is one-way. These could be >> triggered by a periodic task, or by some other event within Ironic, such as >> a change in the power state of a node. >> > > Cool, so this eliminates the need for a separate agent. The ceilometer > work can be done in the collector, to receive the new messages. > > > >> >> >>> >>> 3. Does the current ironic conductor have rpc_method to support getting >>> generic ipmi data, i.e. let the rpc_method caller specifying arbitrary >>> netfn/command to get any type of ipmi data? >>> >> >> No, and as far as I understand, it doesn't need one. >> > > It would only need that if we were going to poll for the data, but if > ironic is emitting notifications then we don't have to do that. > > > >> >> >>> >>> 4. I believe the ironic conductor uses some kind of node_id to associate >>> the bmc with its credentials, right? If so, how can the ceilometer agent >>> get those node_ids to ask the ironic conductor to poll the ipmi data? And >>> how can the ceilometer agent extract meaningful information from that >>> node_id to set those fields in the ceilometer Sample(e.g. recource_id, >>> project_id, user_id, etc.) to identify which physical node the ipmi data is >>> coming from? >>> >> >> This question perhaps requires a longer answer. >> >> Ironic references physical machines (nodes) internally with an integer >> node_id and externally with a standard uuid. When a Nova instance is >> created, it will be associated to a node, that node will have a reference >> to the nova instance_uuid which is exposed in our API, and can be passed to >> Ceilometer's agent. I believe that nova instance_uuid will enable >> ceilometer to detect the project, user, etc. >> > > If ironic has those values (at least the project), and can include them in > the notification payload, that will make processing the incoming > notifications significantly less expensive. > We can take a look as we get closer to completing this. Ironic doesn't know anything about projects today, but we may be able to pass the project_id in from Nova and cache it as a node property for the duration of the instance, if that's an important optimization. -D
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