[Engine-devel] unmanaged devices thrown into 'custom' feature

Yair Zaslavsky yzaslavs at redhat.com
Sun Oct 21 15:38:54 UTC 2012



----- Original Message -----
> From: "Livnat Peer" <lpeer at redhat.com>
> To: "Dan Kenigsberg" <danken at redhat.com>
> Cc: "Genadi Chereshnya" <gcheresh at redhat.com>, engine-devel at ovirt.org, vdsm-devel at fedorahosted.org
> Sent: Sunday, October 21, 2012 5:18:31 PM
> Subject: Re: [Engine-devel] unmanaged devices thrown into 'custom' feature
> 
> On 21/10/12 16:42, Dan Kenigsberg wrote:
> > I have just noticed that when a VM is started for the second time,
> > Engine
> > issues the "create" vdsm verb with some information regarding
> > "unmanaged" devices (an example is shown below[1]) in the 'custom'
> > propery bag.
> > 
> > I'm surprised about this, as I was not aware of this usage of the
> > 'custom' dictionary, and Vdsm is not doing anything with the data.
> > 
> 
> If I recall correctly the idea of passing the unmanaged devices data
> in
> the custom property was to enable managing stable device addresses in
> the hooks (to devices that were added to the VM via hooks from the
> first
> place), so this info is there not for VDSM use.
> For example if you add a device in a hook it will be kept in the
> engine
> as a non managed device. later when starting the VM again you would
> like
> to assign the same device address to your device, and you can do so
> because you have access to the original address in the custom
> properties
> of the VM.

This is exactly what Eli has explained Gendai and Dan today.
However, just to elaborate - these "extra properties" are not stored at the two columns of vm_static (userdefined_properties, predefined_properties) at the DB.

> 
> 
> 
> > Would anyone elaborate about it? On the face of it, it does not
> > seem
> > like a pleasant API. If Engine wants to tell Vdsm about the
> > location of
> > various devices, we should probably be using the 'devices'
> > property, not
> > the bag of 'custom' property made for user-defined hooks.
> > 
> > I hope this API pecularity can be avoided, and very much hope that
> > no
> > one is depending on it.
> > 
> > Dan.
> > 
> > 
> > [1]
> > 'custom': {
> >     'device_e97a9759-1c1b-45ed-9ed9-7136ef538315': 'VmDevice
> >     {vmId=068d4914-4191-400d-a220-17a7f2d8e80c,
> >     deviceId=e97a9759-1c1b-45ed-9ed9-7136ef538315, device=ide,
> >     type=controller, bootOrder=0, specParams={},
> >     address={bus=0x00, domain=0x0000, type=pci, slot=0x01,
> >     function=0x1}, managed=false, plugged=true, readOnly=false,
> >     alias=ide0}',
> >     'device_e97a9759-1c1b-45ed-9ed9-7136ef538315device_133d9bfa-c531-414e-ad20-208d67d5a5e6device_7bfffa34-2e27-4b01-b499-6ac79c997709':
> >     'VmDevice {vmId=068d4914-4191-400d-a220-17a7f2d8e80c,
> >     deviceId=7bfffa34-2e27-4b01-b499-6ac79c997709, device=unix,
> >     type=channel, bootOrder=0, specParams={}, address={port=1,
> >     bus=0, controller=0, type=virtio-serial}, managed=false,
> >     plugged=true, readOnly=false, alias=channel0}',
> >     'device_e97a9759-1c1b-45ed-9ed9-7136ef538315device_133d9bfa-c531-414e-ad20-208d67d5a5e6':
> >     'VmDevice {vmId=068d4914-4191-400d-a220-17a7f2d8e80c,
> >     deviceId=133d9bfa-c531-414e-ad20-208d67d5a5e6,
> >     device=virtio-serial, type=controller, bootOrder=0,
> >     specParams={}, address={bus=0x00, domain=0x0000, type=pci,
> >     slot=0x04, function=0x0}, managed=false, plugged=true,
> >     readOnly=false, alias=virtio-serial0}',
> >     'device_e97a9759-1c1b-45ed-9ed9-7136ef538315device_133d9bfa-c531-414e-ad20-208d67d5a5e6device_7bfffa34-2e27-4b01-b499-6ac79c997709device_7c107c63-605f-4b21-9893-c052ec211424device_48007de9-467d-46a1-aa84-cc1a6419b5fb':
> >     'VmDevice {vmId=068d4914-4191-400d-a220-17a7f2d8e80c,
> >     deviceId=48007de9-467d-46a1-aa84-cc1a6419b5fb,
> >     device=spicevmc, type=channel, bootOrder=0, specParams={},
> >     address={port=3, bus=0, controller=0, type=virtio-serial},
> >     managed=false, plugged=true, readOnly=false, alias=channel2}',
> >     'device_e97a9759-1c1b-45ed-9ed9-7136ef538315device_133d9bfa-c531-414e-ad20-208d67d5a5e6device_7bfffa34-2e27-4b01-b499-6ac79c997709device_7c107c63-605f-4b21-9893-c052ec211424':
> >     'VmDevice {vmId=068d4914-4191-400d-a220-17a7f2d8e80c,
> >     deviceId=7c107c63-605f-4b21-9893-c052ec211424, device=unix,
> >     type=channel, bootOrder=0, specParams={}, address={port=2,
> >     bus=0, controller=0, type=virtio-serial}, managed=false,
> >     plugged=true, readOnly=false, alias=channel1}'
> > }
> > _______________________________________________
> > Engine-devel mailing list
> > Engine-devel at ovirt.org
> > http://lists.ovirt.org/mailman/listinfo/engine-devel
> > 
> 
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