Re: Redesign of QEMU startup & initial configuration

[Daniel P . Berrangé]

On Thu, Dec 09, 2021 at 09:01:24PM +0100, Mark Burton wrote:
> I’ll take the liberty to cut one part (I agree with much of what you say 
> elsewhere)
> 
> > On 9 Dec 2021, at 20:11, Daniel P. Berrangé <berrange@redhat.com> wrote:
> > 
> > As illustrated earlier, I'd really like us to consider being a bit
> > more adventurous on the CLI side. I'm convinced that a CLI for
> > directly configurable hardware is doomed to be horrible no matter
> > what, if you try to directly expose all QAPI configuration
> > flexibilty. Whether key/value, JSON, whatever, it will become
> > unmanagable on the CLI because VM hardware config is inherantly
> > complicated.
> > 
> 
> I absolutely agree, but reach a slightly different conclusion
> 
> > Thus my though that config files or QMP should be the only two
> > places where the full power of QAPI config is exposed. Use CLI
> > as just a way to interact with config files in a simple way
> > with templates.
> 
> I would countenance that we choose only one place to ‘support’ an interface. 
> Either “Yet Another Hardware Configuration Language” or QAPI. Rather than 
> re-inventing that wheel I would simply suggest that we leave that to the 
> relevant ‘user’ community (libvirt, whatever), who have specific requirements 
> and/or existing solutions. Leaving QEMU itself to focus on improving QAPI 
> (and migrating the CLI). 

Yes, indeed, the logical extension of my idea is that the 'simple'
CLI + templating thing doesn't atually have to be in the main QEMU
binary at all. We could in fact ship a bare '/usr/bin/qemu' which
does the config file templating and spawns whatever full QEMU
binary (/usr/bin/qemu-system-blah) does the real VM.  The key is
just that we have something simple for users, who don't want a
full mgmt layer and like the historical QEMU simple configs.


Regards,
Daniel
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