From mboxrd@z Thu Jan 1 00:00:00 1970 From: Nils Cant Subject: KVM doesn't send an arp announce after live migrating a domain Date: Wed, 25 Aug 2010 09:52:16 +0200 Message-ID: <4C74CBB0.7080203@kangaroot.net> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit To: kvm@vger.kernel.org Return-path: Received: from mx-be.kangaroot.net ([62.213.203.171]:47210 "EHLO mx-be.kangaroot.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751207Ab0HYIaK (ORCPT ); Wed, 25 Aug 2010 04:30:10 -0400 Received: from 62-213-203-169.colo.kangaroot.net ([62.213.203.169] helo=zimbra.kangaroot.net) by mx-be.kangaroot.net with esmtp (Exim 4.69) (envelope-from ) id 1OoAnN-0004zA-Gd for kvm@vger.kernel.org; Wed, 25 Aug 2010 09:53:17 +0200 Received: from localhost (localhost.localdomain [127.0.0.1]) by zimbra.kangaroot.net (Postfix) with ESMTP id 61162F4247 for ; Wed, 25 Aug 2010 09:53:14 +0200 (CEST) Received: from zimbra.kangaroot.net ([127.0.0.1]) by localhost (zimbra.kangaroot.net [127.0.0.1]) (amavisd-new, port 10024) with ESMTP id q0eVXBNYh7YO for ; Wed, 25 Aug 2010 09:53:12 +0200 (CEST) Received: from [10.0.14.1] (office2.antwerp.kangaroot.net [82.146.101.162]) by zimbra.kangaroot.net (Postfix) with ESMTPSA id 5A83CF401D for ; Wed, 25 Aug 2010 09:53:12 +0200 (CEST) Sender: kvm-owner@vger.kernel.org List-ID: Hey guys, not sure if this is a bug or a feature request. It's just something we've noticed and are having problems with. We're using the qemu-kvm lenny-backports package on Debian 5.0.5. When doing a live migration from the virsh shell, the server in question becomes unreachable because the ARP cache on our switches still thinks the server is on another port. As soon as the server sends out some traffic, such as a ping, the ARP cache get's updated as expected. If it does nothing, the server remains unreachable until the ARP cache expires on the switches. (in our case 4 hours) We would like to be able to do live migration for customer machines on which we have no access, so we really need KVM to send out an ARP announcement/gratuitous ARP when doing a live migration. Could anyone tell me if this is a bug in KVM, libvirt, or the debian qemu-kvm package? (or if I'm doing something wrong? :-) ) I've been tcpdumping the bridged network interfaces on the hosts while doing the migrate, and couldn't see any ARP broadcasts. Debian 5.0.5 Kernel: 2.6.32-bpo.3-amd64 qemu-kvm 0.12.4+dfsg-1~bpo50+2 libvirt0 0.7.6-1~bpo50+1 migrate --live testserver qemu+ssh://192.168.1.3/system Thanks in advance, Nils