* Daniel P. Berrange (berra...@redhat.com) wrote: > On Thu, Jan 29, 2015 at 03:06:37PM +0000, Dr. David Alan Gilbert (git) wrote: > > From: "Dr. David Alan Gilbert" <dgilb...@redhat.com> > > > > 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" }}
I'm a bit worried about whether starting an incoming migrate afterwards is different in any subtle way. I can see there are a handful of devices that have 'runstate_check(RUN_STATE_INMIGRATE)' calls in, and thus I'm not sure that starting a paused VM and then flipping to RUN_STATE_INMIGRATE would be quite the same. Having said that, we do have 'loadvm' that's similar to an incoming migration. Dave > 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 :| -- Dr. David Alan Gilbert / dgilb...@redhat.com / Manchester, UK