On Wed, Mar 7, 2018 at 1:41 PM, Richard W.M. Jones <rjones@redhat.com> wrote:
On Wed, Mar 07, 2018 at 01:26:39PM +0200, Arik Hadas wrote:
> Interesting, that contradicts my intuition - I would imagine that most of
> the things are actually known (the things that appear in the top-level part
> of the domain xml: memory size, memory size, num of CPUs, name,.. ) and
> only things that depend on the content of the disks or things that depend
> on installations during the conversion are unknown.
> But anyway, it is enough IMO to send the name, memory, CPU and size of the
> disks to present something useful to the user and make the necessary
> validations at that point.

Some of those things are known, but they didn't seem to me to be that
interesting for oVirt to know in advance.  In any case what's
precisely known before conversion is:

(1) The 'source' struct and sub-structs:

https://github.com/libguestfs/libguestfs/blob/ba53251ab912b8bac9e00c1022adc6ba9bdf70a3/v2v/types.mli#L59

(2) The 'overlay' struct (one per disk):

https://github.com/libguestfs/libguestfs/blob/ba53251ab912b8bac9e00c1022adc6ba9bdf70a3/v2v/types.mli#L175

Note only virtual disk size is known, which is near to useless for
provisioning storage.

(3) The 'target' struct (one per disk):

https://github.com/libguestfs/libguestfs/blob/ba53251ab912b8bac9e00c1022adc6ba9bdf70a3/v2v/types.mli#L191

What's unknown are guest capabilities (hence nothing about what
devices should be presented to the guest), inspection data, target bus
mapping, real size of disks, etc.


I see. I think it is sufficient - the information from the 'source' struct seems enough just to produce a representative VM entity in the database that would be reflected in the UI with status 'importing' and for general validations, and the estimated size on the 'target' struct would be enough for storage validations and optionally for choosing the right target storage domain. The other things are relatively hidden in oVirt's UI and can be added at the last phase.

BTW, that's how import from VMware/Xen currently works - we add a VM entity based on the domain XML we get from vCenter and at the last phase add the missing parts when getting the generated OVF from virt-v2v. So for instance, the VM would have no graphics device until that last phase.
 
Rich.

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