On Fri, 20 Mar 2015 16:10:02 +1100 Brett Worth <brett.worth@xxxxxxxxx> wrote: > Hi all. This is my first post to this list and I hope you'll be able to help. > > I have been using the Linux bridge module for a long time under kvm on centos. This has > not given me any problems until now. > > I'm adding some host servers and am using HP BL660 blades. > > The kvm nic script in /etc/kvm creates a tap device then assigns a MAC address after > modifying the first byte to FE. This is so the port 1 host mac doesn't change. > > On a working host server when running brctl showmacs br0 I see the tap mac address and the > mac address assigned to the vm on the same port. The tap mac shows as local and the vm mac > is not. > > The problem: > > Intermittently (once a minute or so) the port number shown for the VM will switch to port > 1. During this time the VM cannot be contacted. The tap device mac remains at it's > original value. If I wait it will switch back to the correct port number i.e. the one > associated with the tap device at which point network connectivity is re-established. > > I have looked for the VM mac address on the LAN but cannot see it so it seems to be > something internal to the bridge. > > Can anyone offer a suggestion as to what might be happening? > > I'm running centos 6.6 and the bridge is 2.3. > > Regards > Brett > No idea, you might try running 'ip monitor' and put output to a log file. Something i changing things underneath you. Maybe Network Manager?
