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On Mon, Aug 30, 2021 at 02:20:54PM +0200, Christophe de Dinechin wrote:
> 
> 
> > On 24 Aug 2021, at 06:34, David Gibson <kata-dev at gibson.dropbear.id.au> wrote:
> > 
> > So.. I just discovered I had a mail misconfiguration which meant at
> > least one recent message I sent to the list on the govmm stuff didn't
> > get through.  Which probably explains why I had a different idea of
> > what was going on that other people seem to have had.
> > 
> > I proposed the integration of govmm into the Kata repository for two
> > reasons:
> > 
> > 1) To avoid the back and forth of synchronized govmm & Kata changes
> > 2) To avoid maintaining another external interface
> > 
> > When I first pitched it to Fabiano I had the impression that Kata was
> > the only user of govmm making it an internal interface in practice, so
> > (1) was the main motivation.  Having discovered that's not the case,
> > though, (2) is really the more important factor.  The Kata team really
> > doesn't have the resources to maintain a general VMM interface - which
> > is in fact an extremely difficult problem (witness the complexity of
> > libvirt).  It's made more difficult by the fact that there's not
> > really a natural API boundary in between qemu itself and Kata's
> > hypervisor interface, so what is and isn't in govmm is already pretty
> > arbitrary and based on Kata's needs.
> > 
> > AIUI, at the last AC meeting, the decision was made to move govmm into
> > the kata-containers repo, encouraging external users to consume it
> > from the new location.  That addresses (1), but not (2), since it's
> > still effectively an external interface.  It makes the dilineation of
> > that interface even less clear than it already is.
> 
> Yes and no. By putting it inside the kata repo, we make it clear
> that it is not a public interface. Anyone using it is at risk of breakage.

Except that that appears to be explicitly *not* the intention.

AIUI, Salvatore (representing the one known external user) was at the
AC meeting, and the decision was to merge the repo but that Salavatore
would consume govmm from the kata-containers repository.  Salvatore's
use was cited as a possible argument against my draft patch to remove
some things that are not used in Kata [0].

In other words, still an external interface in practice.

> What we should do, however, is mark that with a tag or branch so
> that if we create incompatible changes, external users can still
> return to a compatible version. Also maybe add a README pointing
> out that there is no intention to keep the API stable.
> 
> > 
> > So, I really think this is a bad approach.  Instead, what I believe we
> > should do is leave the govmm repository as is, but orphaned, for
> > external users.  They can take up maintenance of it, if they have the
> > interest.  For Kata, I think we should simply fork the current govmm
> > state, removing any parts we don't need, and in future make no attempt
> > to keep it as anything but an internal interface tailored for Kata's
> > needs.  I believe this will let us make some significant
> > simplifications.
> > 
> > My issue and pull request (#2393 and #2395) were made with the latter
> > approach in mind, and I'm presently holding off on merging until we're
> > clear on how we're proceding here.
> > 
> 

[0]
https://github.com/kata-containers/kata-containers/pull/2395#issuecomment-900860876
https://github.com/kata-containers/kata-containers/pull/2395#issuecomment-901653599

-- 
David Gibson			| I'll have my music baroque, and my code
david AT gibson.dropbear.id.au	| minimalist, thank you.  NOT _the_ _other_
				| _way_ _around_!
http://www.ozlabs.org/~dgibson
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