Installation guide
two separate Apache HTTP Server services bound to port 80, because both must bind to
INADDR_ANY instead of the virtual IP addresses.
To configure direct routing using the iptables method, perform the following steps:
1. On each real server, run the following command for every VIP, port, and protocol (TCP or
UDP) combination intended to be serviced for the real server:
iptables -t nat -A PREROUTING -p <tcp|udp> -d <vip> --dport <port> -j
REDIRECT
This command will cause the real servers to process packets destined for the VIP and port
that they are given.
2. Save the configuration on each real server:
# service iptables save
# chkconfig --level 2345 iptables on
The commands above cause the system to reload the iptables configuration on bootup —
before the network is started.
3. Putting the Configuration Together
After determining which of the preceding routing methods to use, the hardware should be linked
together on the network.
Important
The adapter devices on the LVS routers must be configured to access the same
networks. For instance if eth0 connects to public network and eth1 connects to
the private network, then these same devices on the backup LVS router must
connect to the same networks.
Also the gateway listed in the first interface to come up at boot time is added to
the routing table and subsequent gateways listed in other interfaces are ignored.
This is especially important to consider when configuring the real servers.
After physically connecting together the hardware, configure the network interfaces on the
primary and backup LVS routers. This can be done using a graphical application such as
system-config-network or by editing the network scripts manually. For more information about
adding devices using system-config-network, see the chapter titled Network Configuration in
the Red Hat Enterprise Linux Deployment Guide. For the remainder of the chapter, example
alterations to network interfaces are made either manually or through the Piranha
Putting the Configuration Together
29