[Engine-devel] Empty cdrom drive.
Ayal Baron
abaron at redhat.com
Wed Feb 15 09:23:54 UTC 2012
----- Original Message -----
> On 02/15/2012 09:44 AM, Igor Lvovsky wrote:
> > Hi,
> > I want to discuss $subject on the email just to be sure that we all
> > on the
> > same page.
> >
> > So, today in 3.0 vdsm has two ways to create VM with cdrom :
> > 1. If RHEV-M ask to create VM with cdrom, vdsm just create it
> > 2. RHEV-M doesn't ask to create VM with cdrom, vdsm still creates
> > VM with
> > empty cdrom. Vdsm creates this device as 'hdc' (IDE device,
> > index 2),
> > because of libvirt restrictions.
> > In this case RHEV-M will be able to "insert" cdrom on the fly
> > with
> > changeCD request.
> >
> > In the new style API we want to get rid from stupid scenario #2,
> > because
> > we want to be able to create VM without cdrom at all.
> > It means, that now we need to change a little our scenarios:
> > 1. If RHEV-M ask to create VM with cdrom, vdsm just create it
> > 2. RHEV-M doesn't want to create VM with cdrom, but it want to be
> > able to
> > "insert" cdrom on the fly after this. Here we have two
> > options:
> > a. RHEV-M should to pass empty cdrom device on VM creation and
> > use
> > regular changeCD after that
> > b. RHEV-M can create VM without cdrom and add cdrom later
> > through
> > hotplugDisk command.
> >
> > Note: The new libvirt remove previous restriction on cdrom devices.
> > Now
> > cdrom can be created as IDE or VIRTIO device in any index.
> > It means we can easily hotplug it.
>
> I didn't know a CDROM can be a virtio device, but in any way it
> requires
> driver (which may not exist on Windows).
> I didn't know an IDE CDROM can be hot-plugged (only USB-based?),
It can't be hotplugged.
usb based is not ide (the ide device is the usb port, the cdrom is a usb device afaik).
The point of this email is that since we want to support being able to start VMs *without* a cdrom then the default behaviour of attaching a cdrom device needs to be implemented in engine or we shall have a regression.
In the new API (for stable device addresses) vdsm doesn't automatically attach a cdrom.
> perhaps
> I'm wrong here.
> Y.
>
> >
> >
> > Regards,
> > Igor Lvovsky
> >
> >
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> > Engine-devel at ovirt.org
> > http://lists.ovirt.org/mailman/listinfo/engine-devel
>
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