[vbox-dev] how to get the ova version?

Klaus Espenlaub klaus.espenlaub at oracle.com
Fri Oct 4 16:43:14 UTC 2013


On 03.10.2013 03:17, Fei Wang wrote:
> Hi,
> I'm very sorry reply so late.
>>Exactly - if a OVF import would not create a new UUID then VirtualBox would e.g.refuse to import the same OVF file twice.
>>VirtualBox uses the VM UUID to distinguish VMs (we don't require the VM name to be unique, of couse it's a good idea to keep them unique for practical reasons)
>>Can you explain a little more why you need to be able to check the identity,
>>or how you/the used software checks for identity? There might be possibilities,
>>but without context it's impossible to guess what might be interesting for you.
> [context]
> In our software, we need update OVA file on line, so we want to know the
> OVA unique identifier.

There really is no completely unique element in a OVF file (no version 
or UUID), and even if one assumes that the OVA archive is created by 
VirtualBox it isn't possible to distinguish two exports reliably unless 
one digs very deep, by looking at the "modified uuids" of the disk 
images, which VirtualBox maintains.

> If the local OVA file is identical with the remote OVA on http server,
> we needn’t download the remote OVA.

Two OVF files for the same VM (which was modified in the mean time by 
running it and the like) will look the same unless some VM config change 
has been made. Sorry.

> If the local OVA file isn’t identical with the romote OVA, we need
> download the remote OVA to local PC automatically.

If you compare OVA files wholesale then you would see differences, but 
this defeats the purpose of not downloading it all the time, only to 
find out if there is any change or not.

> It's embarrassing if there is no any attribute to identify a OVA file.

Feel free to propose such improvements to the DTMF...

> Maybe we have no choice but to use the name byconventionto identify the
> OVA file.

That's always a way to bend the rules :)
> Thanks,
> Wang Fei

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