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Re: Glance x-image-meta-type raw vs machine


John Purrier sent out an RFC on Dec 30 regarding image conversion (between hypervisor formats or otherwise).  You can get that from the mailing list archive, I presume.  We'll be discussing this lots more over the next weeks and months.



From: Diego Parrilla Santamaría [mailto:diego.parrilla.santamaria@xxxxxxxxx]
Sent: 16 January 2011 22:12
To: Jay Pipes
Cc: Ewan Mellor; openstack@xxxxxxxxxxxxxxxxxxx; John Purrier
Subject: Re: [Openstack] Glance x-image-meta-type raw vs machine

2011/1/14 Jay Pipes <jaypipes@xxxxxxxxx<mailto:jaypipes@xxxxxxxxx>>
2011/1/14 Diego Parrilla Santamaría <diego.parrilla.santamaria@xxxxxxxxx<mailto:diego.parrilla.santamaria@xxxxxxxxx>>:
> Well... VMX is probably too VMware oriented. My only concern about this kind
> of proprietary parameter file is you don't really have the chance to control
> its lifecycle. New versions, changes... and developers lagging behind of
> this changes. It can be a nightmare.
> But this is more a decision of Product Management than a technical
> decision... from my perspective. From a pure user perspective, the more
> options the better, of course.
> BTW, I think we did a good job in Abicloud about virtual disk formats and
> virtual images: http://abiquo.org/display/ABI16/Virtual+Images+Introduction
Helpful link, thanks Diego :)

Followup question, based partly on the table of supported disk
formats: instead of the general VMDK as a disk format, should we have
a more broken-down format for, say, sparse VMDK?

In other words, how fine-grained should the metadata about an image in
Glance be?


I think VMDK subtypes are very relevant information and has to be indicated before a deployment. Just an example: if you try to deploy a streamOptimized or even some sparse formats directly to VMware ESXi they won't work, and troubleshooting for newbies can be complicated.

I'm not very famliar with Glance yet. So may be some of my asumptions can sound stupid...

I guess that one of the main purpose of Glance is to deal with Object Storage Services (Swift or S3 for example) because they are the best candidates to store virtual images. I think this is a 'necessary evil': such a big images must be stored somewhere.

What I don't really get is how Glance is going to deal with all the different virtual images formats supported for the different hypervisors. I mean, who is going to convert from virtual image format X to the virtual image format needed by hypervisor Y? Is Glance responsible for this or the Compute Node? May be if you explain me a little bit how it will work I can be more helpful. I'm still with Austin and I will start to work on the Bexar branch very soon.


Diego Parrilla
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