Networking
For highly redundant server/network setups, need a way to route traffic sensibly when there are two or more equally cabably network interfaces connected to the Internet. Typically such a setup would include a load-balancer upstream of the server which has dual network adaptors.
Enter special service multi-home-route to setup and remove routes and rules to accomplish this.
# ip route 192.168.221.0/24 dev eth0 proto kernel scope link src 192.168.221.100 default via 192.168.221.254 dev eth0 # ip rule 0: from all lookup 255 32766: from all lookup main 32767: from all lookup default # cat /etc/sysconfig/network NETWORKING=yes NETWORKING_IPV6=no HOSTNAME=morbo.mdstage.com # GATEWAY=192.168.221.254 <- remove this # cat /etc/sysconfig/network-scripts/ifcfg-eth0 # Broadcom Corporation NetXtreme II BCM5708 Gigabit Ethernet DEVICE=eth0 BOOTPROTO=static BROADCAST=192.168.221.255 HWADDR=00:1A:A0:38:5F:3E IPADDR=192.168.221.100 NETMASK=255.255.255.0 NETWORK=192.168.221.0 GATEWAY=192.168.221.254 <- add this ONBOOT=yes # cat /etc/sysconfig/network-scripts/ifcfg-eth1 # Broadcom Corporation NetXtreme II BCM5708 Gigabit Ethernet DEVICE=eth1 BOOTPROTO=static BROADCAST=192.168.222.255 HWADDR=00:1A:A0:38:5F:40 IPADDR=192.168.222.100 NETMASK=255.255.255.0 NETWORK=192.168.222.0 GATEWAY=192.168.222.254 <- add this ONBOOT=yes # cat /etc/iproute2/rt_tables # # reserved values # 255 local 254 main 253 default 0 unspec # # local # #1 inr.ruhep 21 connection1 <- add this 22 connection2 <- add this # who -r run-level 3 2009-10-06 16:28 last=S |
# cd /etc/rc.d # grep -R multi- * init.d/multi-home-route:# multi-home-route ... init.d/multi-home-route:# description: ... rc3.d/S11multi-home-route:# multi-home-route ... rc3.d/S11multi-home-route:# description: ... rc5.d/S11multi-home-route:# multi-home-route ... rc5.d/S11multi-home-route:# description: ... $ ls -lh /etc/rc.d/rc3.d/*multi-home* lrwxrwxrwx 1 root root 26 Oct 7 16:37 /etc/rc.d/rc3.d/S11multi-home-route -> ../init.d/multi-home-route $ ls -lh /etc/rc.d/rc5.d/*multi-home* lrwxrwxrwx 1 root root 26 Oct 7 16:38 /etc/rc.d/rc5.d/S11multi-home-route -> ../init.d/multi-home-route # ip route 192.168.221.0/24 dev eth0 proto kernel scope link src 192.168.221.100 192.168.222.0/24 dev eth1 proto kernel scope link src 192.168.222.100 169.254.0.0/16 dev eth1 scope link default via 192.168.222.254 dev eth1 # ip rule 0: from all lookup 255 10: from 192.168.221.0/24 lookup connection1 20: from 192.168.222.0/24 lookup connection2 32766: from all lookup main 32767: from all lookup default |