[Engine-devel] new engine watchdog version

[Laszlo Hornyak]

----- Original Message -----
> From: "Omer Frenkel" <ofrenkel at redhat.com>
> To: "Laszlo Hornyak" <lhornyak at redhat.com>
> Cc: "engine-devel" <engine-devel at ovirt.org>
> Sent: Sunday, March 10, 2013 8:36:46 AM
> Subject: Re: [Engine-devel] new engine watchdog version
> 
> 
> 
> ----- Original Message -----
> > From: "Laszlo Hornyak" <lhornyak at redhat.com>
> > To: "engine-devel" <engine-devel at ovirt.org>
> > Sent: Friday, March 8, 2013 7:18:59 PM
> > Subject: [Engine-devel] new engine watchdog version
> > 
> > Hi,
> > 
> > I uploaded a new version of the watchdog patch. This patch is still
> > a
> > work in progress, it adds audit log alerts to the functionality.
> > http://gerrit.ovirt.org/12419/
> > 
> > Feature page:
> > http://www.ovirt.org/Features/Watchdog_engine_support
> > 
> > Laszlo
> > _______________________________________________
> > Engine-devel mailing list
> > Engine-devel at ovirt.org
> > http://lists.ovirt.org/mailman/listinfo/engine-devel
> > 
> 
> Hi,
> i looked at the patch and there is something i don't understand,
> i see you are treating the watchdog as a vm device, which is great,
> so why do we need to save the device details in vm_static table in
> addition to the vm_devices?
> i think its even not used at all (only setting the device in command
> which could be parameters, no need to persist)
> 

Hi Omer,

Thanks, I hoped someone will come up with that question :) The answer is that I followed the established design patterns in the backend. See smartcard and memory balloon, probably others. The motivation for this pattern could be that in case of these devices, you must have the settings in the VM data, not separately in the devices. Also when vdsbroker builds the devices list, it just asks the device list. The redundancy is already there, we can make it differently in this case but that will present the readers with a puzzle: why this pattern in feature X, why that pattern in feature Y...
So I would recommend to leave it like this for now and schedule a cleanup on device handling. Devices deserve a cleanup.

Thx,
Laszlo