* Daniel P. Berrange (berra...@redhat.com) wrote: > On Thu, Jan 08, 2015 at 11:11:29AM +0000, Dr. David Alan Gilbert (git) wrote: > > From: "Dr. David Alan Gilbert" <dgilb...@redhat.com> > > > > If the remote host, or networking dies during a migration, the socket can be > > waiting for a long timeout, and migration_cancel can't complete the cancel > > for a long time (and you can't start a new one to somewhere else). > > (Where 'long' is the TCP timeout, that's ~15 mins) > > > > This patch set uses the shutdown(2) syscall to unblock any write/sends that > > are in progress to let the migrate_cancel happen quickly. > > > > 1/3: socket shutdown - An updated patch from my postcopy world to > > add a shut_down method on QEMUFile - only > > for 'socket' (where the syscall is supported). > > > > 2/3: Handle bi-directional communication for fd migration > > - A patch from Cristian Klein to use the socket > > QEMUFile for FDs that are passed in, if the FDs > > are sockets; this is needed so that libvirt > > migrations can take advantage of the other > > patches. > > Again this patch (and its naming) come from the > > postcopy world. > > > > 3/3: migration_cancel: shutdown migration socket > > - A new patch that uses the shutdown in > > migrate_fd_cancel > > > > > > Note this does not fix the timeout if you try to migrate to an already dead > > host; > > the connect timeout is typically a much shorter 2 minutes anyway. > > In any libvirt managed setup, you'd need to address the connect timeout > issue in libvirt instead, since libvirt always uses fd based migration. > ie libvirt estabishes the connection & then passes the TCP Socket to > QEMU. > > It should be possible for libvirt to use a non-blocking connect() > call and catch use of its virDomainMigrateCancel APi to stop the > connection attempt.
Yes, although as I say I've not fixed the (must shorter) connect side timeout on the QEMU side either. How does libvirt behave if you cancel a tunnelled migration with the network dieing in the middle? 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
