From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:53198) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1Y9BB0-0007oa-9v for qemu-devel@nongnu.org; Thu, 08 Jan 2015 06:22:55 -0500 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1Y9BAx-00039c-1U for qemu-devel@nongnu.org; Thu, 08 Jan 2015 06:22:54 -0500 Received: from mx1.redhat.com ([209.132.183.28]:56329) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1Y9BAw-00038y-R5 for qemu-devel@nongnu.org; Thu, 08 Jan 2015 06:22:50 -0500 Date: Thu, 8 Jan 2015 11:22:42 +0000 From: "Daniel P. Berrange" Message-ID: <20150108112242.GB12056@redhat.com> References: <1420715492-5109-1-git-send-email-dgilbert@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline In-Reply-To: <1420715492-5109-1-git-send-email-dgilbert@redhat.com> Subject: Re: [Qemu-devel] [PATCH 0/3] Migration cancel with dead network Reply-To: "Daniel P. Berrange" List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: "Dr. David Alan Gilbert (git)" Cc: amit.shah@redhat.com, cristian.klein@cs.umu.se, qemu-devel@nongnu.org, quintela@redhat.com On Thu, Jan 08, 2015 at 11:11:29AM +0000, Dr. David Alan Gilbert (git) wrote: > From: "Dr. David Alan Gilbert" > > 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. 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 :|