[Libguestfs] Appliance image. Why raw?

Pavel Butsykin pbutsykin at virtuozzo.com
Tue Jun 20 16:12:20 UTC 2017


On 20.06.2017 19:06, Richard W.M. Jones wrote:
> On Tue, Jun 20, 2017 at 06:48:16PM +0300, Pavel Butsykin wrote:
>> On 20.06.2017 18:41, Richard W.M. Jones wrote:
>>> On Tue, Jun 20, 2017 at 06:34:28PM +0300, Pavel Butsykin wrote:
>>>> On 20.06.2017 17:47, Richard W.M. Jones wrote:
>>>>> On Tue, Jun 20, 2017 at 05:04:53PM +0300, Pavel Butsykin wrote:
>>>>>> I noticed that raw is intentionally used as image format for appliance
>>>>>> image. So I would like to ask, is there any reason to use raw as image
>>>>>> format for appliance?
>>>>>
>>>>> The simple answer is because we create the appliance image (it's an
>>>>> ext2/3/4 filesystem) using e2fsprogs, and that library wouldn't know
>>>>> how to create anything else since it always assumes it's writing
>>>>> directly to a device.
>>>>>
>>>>> https://github.com/libguestfs/supermin/blob/master/src/format_ext2.mli#L22-L29
>>>>>
>>>>> HTH,
>>>>
>>>> Yes, the main point is clear, thanks.
>>>>
>>>> I asked because we supply the prepared appliance, so would like to use
>>>> qcow2. Given that the applaince image is completely controlled, for
>>>> supermin and fixed appliance, in both the cases. We could use
>>>> autodetect, it is already implemented in qemu, so to add it to
>>>> libguestfs will simply. I'm going to prepare the patches, what do you
>>>> think?
>>>
>>> ./configure-time option? >
>>> Autodetection is actually not insecure with modern qemu, but people
>>> still think it is ...
>>
>> Yes, but in our case it will be safe, because we have full control over
>> appliance image.
> 
> As long as a configure time option will work for you, I'd
> prefer to do that.
>

Yes, the configure time option to enable autodetection of appliance
image format will be fine, thanks!

> Rich.
> 




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