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.

Regards, Igor Lvovsky _______________________________________________ Engine-devel mailing list Engine-devel(a)ovirt.org http://lists.ovirt.org/mailman/listinfo/engine-devel

From: "Ayal Baron" <abaron(a)redhat.com&gt; To: "Yaniv Kaul" <ykaul(a)redhat.com&gt; Cc: engine-devel(a)ovirt.org Sent: Wednesday, February 15, 2012 11:23:54 AM Subject: Re: [Engine-devel] Empty cdrom drive. ----- 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 > > > > > > _______________________________________________ > > Engine-devel mailing list > > Engine-devel(a)ovirt.org > > http://lists.ovirt.org/mailman/listinfo/engine-devel > > _______________________________________________ > Engine-devel mailing list > Engine-devel(a)ovirt.org > http://lists.ovirt.org/mailman/listinfo/engine-devel > _______________________________________________ Engine-devel mailing list Engine-devel(a)ovirt.org http://lists.ovirt.org/mailman/listinfo/engine-devel

-----Original Message----- From: engine-devel-bounces(a)ovirt.org

On Behalf Of Livnat Peer Sent: Sunday, February 19, 2012 1:07 PM To: Dan Kenigsberg Cc: engine-devel(a)ovirt.org; arch(a)ovirt.org Subject: Re: [Engine-devel] Empty cdrom drive. On 15/02/12 11:29, Miki Kenneth wrote: > > > ----- Original Message ----- >> From: "Ayal Baron" <abaron(a)redhat.com&gt; >> To: "Yaniv Kaul" <ykaul(a)redhat.com&gt; >> Cc: engine-devel(a)ovirt.org >> Sent: Wednesday, February 15, 2012 11:23:54 AM >> Subject: Re: [Engine-devel] Empty cdrom drive. >> >> >> >> ----- 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. >>>> The preferred solution IMO would be to let the user choose if he wants a VM with CD or not. I think the motivation for the above is to 'save' IDE slot if a user does not need CD. If the user wants to have a VM with CD the engine would create an empty CD and pass it to VDSM as a device, but if the user does not require a CD there is no reason to create it in VDSM nor in the OE (oVirt Engine). Supporting the above requires the engine upgrade to create empty CD device to all VMs.

Dan - what happens in 3.0 API if the engine passes the element cdrom but with empty path attribute. (I know that if the engine does not pass cdrom element VDSM creates empty CD)