[Bug 584048] Re: kvm images losing connectivity w/bridged network

[Andrew Klettke]

I'm also having this problem. Running 10.04 with KVM and Libvirt,
starting VMs with "virsh start <domain>"

I've tested with OpenBSD 4.7 and Debian Lenny 5.0.5, both of them are
having this issue.

I notice that networking with the bridge works fine at first for my
guests, but after a while, the bridge stops functioning, and I can't
reach it via SSH, nor can I ping/ssh out.

Also, when this happens, the ARP entry on the firewall I'm using to SSH
to the guest changes from the Guest's MAC to the Host's MAC address.

On OpenBSD, if I run the /etc/netstart script to re-initialize the
interface, the bridge starts functioning again, as if I restarted the
VM, but quickly fails again (10-20 minutes). I have to reboot the Debian
machine to get networking functioning again.

Here is my /etc/network/interfaces on the host:
# The loopback network interface
auto lo
iface lo inet loopback

# The primary network interface
auto eth0
iface eth0 inet dhcp

auto br0
iface br0 inet static
	address 192.168.8.166
	netmask 255.255.252.0
	network 192.168.8.0
	broadcast 192.168.11.255
	gateway 192.168.8.1
	bridge_ports eth1
	bridge_fd 9
	bridge_hello 2
	bridge_maxage 12
	bridge_stp off

And my /etc/libvirt/qemu/networks/autostart/default.xml:
<network>
  <name>default</name>
  <bridge name="virbr%d" />
  <forward/>
  <ip address="192.168.122.1" netmask="255.255.255.0">
    <dhcp>
      <range start="192.168.122.2" end="192.168.122.254" />
    </dhcp>
  </ip>
</network>

-- 
kvm images losing connectivity w/bridged network
https://bugs.launchpad.net/bugs/584048
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