[openstack-dev] RFC: Recording/providing ISO image headers in glance

Mac Innes, Kiall kiall at hp.com
Wed Jan 30 11:30:14 UTC 2013

Apologies - Just noticed the "or part of" after hitting send!

I'm assuming that means you already considered this option.


On 30/01/13 11:28, Mac Innes, Kiall wrote:
> Just throwing this out there, I don't necessarily have an opinion either
> way..
> What about using the HTTP Range header to ask for the first X bytes of
> the image? This certainly isn't as efficient for the client as a
> dedicated API endpoint, but would not require explicit support for
> individual formats to be implemented.
> (I'm assuming there is some sort of fixed maximum length for the ISO header)
> Thanks,
> Kiall
> On 30/01/13 10:58, Daniel P. Berrange wrote:
>> Some apps have a need to be able to obtain ISO filesystem headers from
>> images stored in glance. Now obviously they can just download the image
>> (or part of it) and run 'isoinfo' on it, but this is really horrifically
>> inefficient/wasteful of bandwidth. It would be desirable for glance to
>> have explicit support for this in some way.
>> I've written a short wiki page describing one approach, which is to
>> make glance extract the data upon upload of an ISO and store it in
>> some well-defined metadata properties against the image.
>>     http://wiki.openstack.org/GlanceISOHeaders
>>     https://blueprints.launchpad.net/glance/+spec/iso-image-metadata
>> A completely different approach we be to ignore metadata properties
>> and add an explicit API to glance which would extract it on-demand,
>> but I feel this is a needlessly large amount of work & less convenient
>> and flexible than simply using existing metadata properties.
>> Regards,
>> Daniel

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