Greetings, I''m having a problem with live migration, and the default network settings used by Xen. I was hoping someone could give me advise on what I''m doing wrong. I currently have three Linux installations, two of the PCs are running SuSe 9.1/Xen 2.0.5 with the stock xenU and xen0. The third PC is running coLinux (debian) on a WindowsXP machine that exports the Xen''s test ttylinux distribution in a flat file. For this setup I have both Xen hosts NFS mount a directory containing the image. I start a ping process on one of the Xen hosts to monitor network connectivity. I then live migrate the VM from one to host to the other. The ping process will usually fail for approximatley 15-20 seconds (sometimes upto ~50 seconds), and then eventually restart. The VM migrates properly. I''ve looked at several tcpdump traces to see if I could find the unsolicited arp being sent, but I don''t. In fact I see the Xen host with the ping process re-issue the arp to find the IP address, and then the pings succeed. I added some debug code to the netfront driver to verify that the arp is in fact being queued, and everything looks fine. I started to suspect that something is wrong with my bridge setup. I started out using the default Xen vif-bridge scripts, but I found that the VM only had connectivity to dom0. The VM wasn''t able to ping other hosts on the subnet. From my googling, I discovered that people had similar problems, and based on their success I changed my init scripts. Instead of Xen creating the bridge, I create my own, and label it eth0. I do this before the init scripts configure eth0. /sbin/ip link set name hw-eth0 dev eth0 /sbin/brctl addbr eth0 /sbin/brctl addif eth0 hw-eth0 /sbin/ip link set up hw-eth0 This works well for me. I''ve also tried the routing setup, but I still had problems reaching other hosts from the VM. While I''m able to migrate domains, I am unable to match the times I had read in the literature (<1 second). Any ideas on where I went wrong, or areas that I should be looking at? Thanks, Christopher ------------------------------------------------------- SF email is sponsored by - The IT Product Guide Read honest & candid reviews on hundreds of IT Products from real users. Discover which products truly live up to the hype. Start reading now. http://ads.osdn.com/?ad_id=6595&alloc_id=14396&op=click _______________________________________________ Xen-devel mailing list Xen-devel@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/xen-devel
> For this setup I have both Xen hosts NFS mount a directory containing > the image. I start a ping process on one of the Xen hosts to monitor > network connectivity. I then live migrate the VM from one to host to > the other. The ping process will usually fail for > approximatley 15-20 > seconds (sometimes upto ~50 seconds), and then eventually > restart. The > VM migrates properly.How are your various machines interconnected? Are they all on the same subnet (via an Ethernet switch), or are they routed?> I started to suspect that something is wrong with my bridge setup. I > started out using the default Xen vif-bridge scripts, but I > found that > the VM only had connectivity to dom0. The VM wasn''t able to > ping other > hosts on the subnet. From my googling, I discovered that people had > similar problems, and based on their success I changed my > init scripts. > Instead of Xen creating the bridge, I create my own, and label it > eth0. I do this before the init scripts configure eth0.Calling it eth0 seems a very odd thing to do, but I guess it would work. Ian ------------------------------------------------------- SF email is sponsored by - The IT Product Guide Read honest & candid reviews on hundreds of IT Products from real users. Discover which products truly live up to the hype. Start reading now. http://ads.osdn.com/?ad_ide95&alloc_id396&op=click _______________________________________________ Xen-devel mailing list Xen-devel@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/xen-devel
Christopher Boumenot
2005-Mar-16 14:10 UTC
[Xen-devel] Re: Live Migration and Bridge Settings
Ian Pratt wrote:>>For this setup I have both Xen hosts NFS mount a directory containing >>the image. I start a ping process on one of the Xen hosts to monitor >>network connectivity. I then live migrate the VM from one to host to >>the other. The ping process will usually fail for >>approximatley 15-20 >>seconds (sometimes upto ~50 seconds), and then eventually >>restart. The >>VM migrates properly. > > > How are your various machines interconnected? Are they all on the same > subnet (via an Ethernet switch), or are they routed? >All of the hosts are connected through a switch, and they are all on the same subnet. Chris ------------------------------------------------------- SF email is sponsored by - The IT Product Guide Read honest & candid reviews on hundreds of IT Products from real users. Discover which products truly live up to the hype. Start reading now. http://ads.osdn.com/?ad_id=6595&alloc_id=14396&op=click _______________________________________________ Xen-devel mailing list Xen-devel@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/xen-devel
> > How are your various machines interconnected? Are they all > on the same > > subnet (via an Ethernet switch), or are they routed? > > > > All of the hosts are connected through a switch, and they are > all on the same subnet.In which case the unsolicited ARP response shouldn''t be necessary -- the Ethernet switch should reconfigure as soon as it sees the VM''s MAC address active on another port (assuming you''re using bridging within each dom0 rather than routing). I have seen some crappy Ethernet switches that react badly to MAC addresses moving, but most work fine. What happens if you migrate a domain that is running a ping? Does the act of it sending packets cause the switch to reconfigure quicker? Also, are you giving the -l option to migrate? Ian ------------------------------------------------------- SF email is sponsored by - The IT Product Guide Read honest & candid reviews on hundreds of IT Products from real users. Discover which products truly live up to the hype. Start reading now. http://ads.osdn.com/?ad_ide95&alloc_id396&op=click _______________________________________________ Xen-devel mailing list Xen-devel@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/xen-devel