Installation guide

Chapter 9. Setting Up a Red Hat Enterprise Linux LVS Cluster 105

After conﬁguring the primary LVS router node’s network interfaces, conﬁgure the backup

LVS router’s real network interfaces — taking care that none of the IP address conﬂict with

any other IP addresses on the network.

Important

Be sure each interface on the backup node services the same network as the interface on

primary node. For instance, if eth0 connects to the public network on the primary node, it

must also connect to the public network on the backup node as well.

9.1.2. Routing on the Real Servers

The most important thing to remember when conﬁguring the real servers network inter-

faces in a NAT cluster is to set the gateway for the NAT ﬂoating IP address of the LVS

router. In this example, that address will be 10.11.12.10.

Note

Once the network interfaces are up on the real servers, the machines will be unable to

ping or connect in other ways to the public network. This is normal. You will, however, be

able to ping the real IP for the LVS router’s private interface, in this case 10.11.12.8.

So the real server’s /etc/sysconfig/network-scripts/ifcfg-eth0 ﬁle could look

similar to this:

DEVICE=eth0

ONBOOT=yes

BOOTPROTO=static

IPADDR=10.11.12.1

NETMASK=255.255.255.0

GATEWAY=10.11.12.10

Warning

If a real server has more than one network interface conﬁgured with a GATEWAY= line, the

ﬁrst one to come up will get the gateway. Therefore if both eth0 and eth1 are conﬁgured

and eth1 is used for LVS clustering, the real servers may not route requests properly.