Installation guide

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

# chkconfi g --l evel 2345 iptables o n

The commands above cause the system to reload the iptables configuration on bootup —

before the network is started.

3.3. 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 Configuration Tool.

3.3.1. General LVS Networking Tips

Configure the real IP addresses for both the public and private networks on the LVS routers before

attempting to configure LVS using the Piranha Configuration Tool. T he sections on each topology

give example network addresses, but the actual network addresses are needed. Below are some useful

commands for bringing up network interfaces or checking their status.

Bringing Up Real Network Int erfaces

To bring up a real network interface, use the following command as root, replacing N with the

number corresponding to the interface (eth0 and eth1).

/sbin/ifup ethN

Chapter 3. Setting Up LVS