On Fri, Aug 26, 2011 at 12:17:58PM +0200, Gerd Hoffmann wrote: > On 08/26/11 12:03, Daniel P. Berrange wrote: > >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) > > >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. > > Ok, so I think we should be able to fix the race outlined above > without adding new monitor commands, just by letting libvirt set the > spice ticket in stage 2.
Is that different then what I suggested in my reply to Daniel's 5 stage outline? > > cheers, > Gerd > >
