Re: [Engine-devel] new engine watchdog version

From: "Laszlo Hornyak" <lhornyak(a)redhat.com&gt; To: "Omer Frenkel" <ofrenkel(a)redhat.com&gt; Cc: "engine-devel" <engine-devel(a)ovirt.org&gt; Sent: Monday, March 11, 2013 6:46:06 PM Subject: Re: [Engine-devel] new engine watchdog version ----- Original Message ----- > From: "Omer Frenkel" <ofrenkel(a)redhat.com&gt; > To: "Laszlo Hornyak" <lhornyak(a)redhat.com&gt; > Cc: "engine-devel" <engine-devel(a)ovirt.org&gt; > Sent: Monday, March 11, 2013 1:25:39 PM > Subject: Re: [Engine-devel] new engine watchdog version > > > > ----- Original Message ----- > > From: "Laszlo Hornyak" <lhornyak(a)redhat.com&gt; > > To: "Omer Frenkel" <ofrenkel(a)redhat.com&gt; > > Cc: "engine-devel" <engine-devel(a)ovirt.org&gt; > > Sent: Monday, March 11, 2013 12:15:39 PM > > Subject: Re: [Engine-devel] new engine watchdog version > > > > > > > > ----- Original Message ----- > > > From: "Omer Frenkel" <ofrenkel(a)redhat.com&gt; > > > To: "Laszlo Hornyak" <lhornyak(a)redhat.com&gt; > > > Cc: "engine-devel" <engine-devel(a)ovirt.org&gt; > > > Sent: Monday, March 11, 2013 11:12:48 AM > > > Subject: Re: [Engine-devel] new engine watchdog version > > > > > > > > > > > > ----- Original Message ----- > > > > From: "Laszlo Hornyak" <lhornyak(a)redhat.com&gt; > > > > To: "Omer Frenkel" <ofrenkel(a)redhat.com&gt; > > > > Cc: "engine-devel" <engine-devel(a)ovirt.org&gt; > > > > Sent: Monday, March 11, 2013 9:59:53 AM > > > > Subject: Re: [Engine-devel] new engine watchdog version > > > > > > > > > > > > > > > > ----- Original Message ----- > > > > > From: "Omer Frenkel" <ofrenkel(a)redhat.com&gt; > > > > > To: "Laszlo Hornyak" <lhornyak(a)redhat.com&gt; > > > > > Cc: "engine-devel" <engine-devel(a)ovirt.org&gt; > > > > > Sent: Sunday, March 10, 2013 8:36:46 AM > > > > > Subject: Re: [Engine-devel] new engine watchdog version > > > > > > > > > > > > > > > > > > > > ----- Original Message ----- > > > > > > From: "Laszlo Hornyak" <lhornyak(a)redhat.com&gt; > > > > > > To: "engine-devel" <engine-devel(a)ovirt.org&gt; > > > > > > 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(a)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 > > > > > > > > > > i agree there is a mess that requires clean-up, > > > but i don't think its a good thing to keep piling up the mess, > > > i don't like it that smartcard is there, but some other devices > > > are > > > ok (balloon and payload) > > > so we already have 2 'patterns', lets go with the right one.. > > > and answering also @Doron's question - yes the device data > > > should > > > be > > > kept with the device > > > > > > > Ok, I may have missed the other pattern, could you explain which > > one > > do you mean? > > Balloon does not very different from smartcard, it is there in > > VM. > > > > the difference is that balloon is not in vm_static table at all > (the > only place in the db for it is in vm_devices) > and smartcard has 'is_smartcard_enabled' field in vm_static in > addition to vm_devices (which is not needed..) Ok, so what you want is that - the engine should query the devices each time the VM record is set (from DAO's or Action) XOR - the client code (rest-api and frontend) should query the devices to figure out if the watchdog is there

> > the way i think we (currently) need to work with devices is: > add a parameter for it in the parameters, and use it in add/update > (/run-once?) (as done for balloon) run once for watchdog? why?

> i don't know what is the use of the field balloonEnabled in VM, i > don't see any use of it.. It is a write-only property. > > going forward we need to think if we want to expose devices to > frontend, > so then we can drop the encapsulation and just use list of devices > in > VmBase or something like that >