From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([140.186.70.92]:47894) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1QwtGL-0000uh-T9 for qemu-devel@nongnu.org; Fri, 26 Aug 2011 06:03:46 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1QwtGK-0000tz-FX for qemu-devel@nongnu.org; Fri, 26 Aug 2011 06:03:45 -0400 Received: from mx1.redhat.com ([209.132.183.28]:41609) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1QwtGK-0000tv-3r for qemu-devel@nongnu.org; Fri, 26 Aug 2011 06:03:44 -0400 Received: from int-mx02.intmail.prod.int.phx2.redhat.com (int-mx02.intmail.prod.int.phx2.redhat.com [10.5.11.12]) by mx1.redhat.com (8.14.4/8.14.4) with ESMTP id p7QA3hJ8019871 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-SHA bits=256 verify=OK) for ; Fri, 26 Aug 2011 06:03:43 -0400 Date: Fri, 26 Aug 2011 11:03:38 +0100 From: "Daniel P. Berrange" Message-ID: <20110826100338.GH3944@redhat.com> References: <1313773728-6104-1-git-send-email-alevy@redhat.com> <4E576D69.8020103@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline In-Reply-To: <4E576D69.8020103@redhat.com> Subject: Re: [Qemu-devel] [PATCH 0/3] client_migrate_switch and auto_switch (RHBZ 725009) Reply-To: "Daniel P. Berrange" List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Gerd Hoffmann Cc: Alon Levy , qemu-devel@nongnu.org On Fri, Aug 26, 2011 at 11:54:49AM +0200, Gerd Hoffmann wrote: > On 08/19/11 19:08, Alon Levy wrote: > >Fix the ticket expiration on target vm for a spice connection without introducing > >a race between the spice server switching the client to the new host itself and > >the target libvirt setting the new expiration date, by adding an option to > >client_migrate_info to not automatically switch the client on migration completion, > >instead waiting for an explicit client_migrate_switch (new monitor command) from > >libvirt. > > Hmm. Guess the fundamental issue is that libvirt wants to use the > monitor to set the ticket instead of the command line for security > reasons. The qemu monitor doesn't accept commands while the > incoming migration is running. We also can't kick the incoming > migration via monitor, so first setting the ticket then start > migration doesn't work too. Correct? There is actually a reliable window where we can use the monitor before incoming migration starts. Libvirt's migration is a 5 stage handshake: 1. Begin(src) - Gets current source VM XML config 2. Prepare(dst) - Launches QEMU -incoming - Sets passwords, etc to monitor 3. Perform(src) - Issue migrate_client_info - Issue migrate_set_speed - Issue migrate - Loop - Issue query-migrate - Break if finished/failed 4. Finish(dst) - If success - start CPUs Else - Kill QEMU 5. Confirm(src) - If success - Kill QEMU Else - Restart CPUs Those stages are all serialized, so we can do anything we like with the QEMU monitor at stage 2, before stage 3 will start back on the src. 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 :|