Re: [Qemu-devel] [RFC 1/1] Execute arbitrary QMP commands from command line

[Daniel P. Berrange]

On Thu, Jan 29, 2015 at 03:06:37PM +0000, Dr. David Alan Gilbert (git) wrote:
> From: "Dr. David Alan Gilbert" <address@hidden>
> 
> For an incoming migration it's potentially useful to be able to set
> capabilities and parameters prior to opening the connection, while
> a separate option for that would have been possible it seems better
> to give access to all the existing migration capabilities, parameters
> etc.  The least restrictive way of doing this is to allow arbitrary
> QMP commands to be executed prior to the -incoming being processed.
> 
> As an example:
> 
> ./bin/qemu-system-x86_64 -nographic -nodefaults -qmp-command '{"execute": 
> "migrate-set-capabilities", 
> "arguments":{"capabilities":[{"capability":"xbzrle","state":true}]}}' 
> -qmp-command '{"execute": "query-migrate-capabilities"}' -incoming tcp::444

I'm unclear how we'd easily deal with the response from commands
invoked this way, to get replies and/or errors. Also, it might
be the case that we need to conditionally run certain commands
depending on the result of earlier commands.

Wouldn't it make more sense to simply add a 'migrate_incoming' QMP
command, and stop using -incoming altogether, so we just have normal
QMP access ?

eg,

    #  qemu-system-x86_64 ....device args...  -S
    (qmp) ....arbitrary QMP commands ..
    (qmp) {"execute":"migrate-incoming", "arguments": { "uri": "tcp::44" }}

Regards,
Daniel
-- 
|: http://berrange.com      -o-    http://www.flickr.com/photos/dberrange/ :|
|: http://libvirt.org              -o-             http://virt-manager.org :|
|: http://autobuild.org       -o-         http://search.cpan.org/~danberr/ :|
|: http://entangle-photo.org       -o-       http://live.gnome.org/gtk-vnc :|