HOWTO configure bonding and bridging
For high-availability of a KVM system you need to combine bonding and bridging of the network. On Debian GNU/Linux (here squeeze 6.0) you can configure it this way:
/etc/network/interfaces
# This file describes the network interfaces available on your system
# and how to activate them. For more information, see interfaces(5).
# The loopback network interface
auto lo
iface lo inet loopback
auto bond0
iface bond0 inet manual
slaves eth0 eth1
bond_mode active-backup
bond_miimon 100
bond_downdelay 200
bond_updelay 200
auto br0
iface br0 inet static
address 1.2.3.4
netmask 255.255.255.0
gateway 1.2.3.254
bridge_ports bond0
bridge_stp off
bridge_fd 9
bridge_hello 2
bridge_maxage 12
bridge_maxwait 0
# dns-* options are implemented by the resolvconf package, if installed
dns-nameservers 1.2.3.254
dns-search domain.lan
Only bonding mode active-backup (1) or 802.3ad (4) modes run fine. Else you will get network problems and get error messages like "br0: recieved packet on bond0 with own address as source address".
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