[et-mgmt-tools] Re: [virt-tools-list] RFC: virt-manager: VM clone wizard

[Cole Robinson]

Daniel P. Berrange wrote:
> On Mon, Jul 20, 2009 at 01:11:29PM -0400, Cole Robinson wrote:
>> Hi all,
>>
>> The attached patch adds a small wizard for cloning a VM. A screenshot of
>> the overview:
>>
>> http://fedorapeople.org/~crobinso/virt-manager/clone-post/vmm-clone-overview.png
>>
>> The wizard will generate a new VM name (usually <orig-name>-clone), new
>> storage paths as required, and MAC addresses. Storage is marked as
>> one of:
>>
>> - Shared: Original and clone VM point to the same disk image
>> - Clone : Actually copy the original storage for use by the clone
>>
>> Storage like removable media (cdrom, floppy), readonly or shareable
>> disks will be 'Shared' by default.
>>
>> The storage drop down has a 'Details' choice:
>>
>> http://fedorapeople.org/~crobinso/virt-manager/clone-post/vmm-clone-dropdown.png
>>
>> This brings up a small dialog which allows changing the new disk path:
>>
>> http://fedorapeople.org/~crobinso/virt-manager/clone-post/vmm-clone-storage-details.png
>>
>> There is also a similar dialog for changing MAC addresses.
>>
>> If we can't clone storage (maybe lack of permissions, or remote
>> unmanaged storage, older libvirt), we still allow cloning the VM, but
>> force the offending disks into 'Shared' mode. In the case of sharing a
>> read/write disk, we give a clear warning that this may result in
>> overwriting the original image.
> 
> IMHO, we should simply disallow that. Users would expect that
> cloning a guest is guarneteed to not impact the original. If
> we can't guarentee that, we should refuse to clone it. Swiching
> a private disk to shared mode is giving a user a loaded gun
> with no safety catch & a touch sensitive trigger.
> 

Are you saying we should disallow sharing any private disks, or only
ones that it appears we can't clone? I suppose any shareable disks
should be marked with <shareable/> in the XML, but that currently isn't
obvious to the user, or easy via any of the tools atm.  The cases when a
user would actually want to share a r/w disk though are rare enough that
we should require the sharable flag, and deny the clone operation otherwise.

- Cole