User Guide

334 Chapter 15 Optimizing ClusterCATS
ClusterCATS Dynamic IP Addressing (Windows only)
This section describes how to enable ClusterCATS dynamic IP addressing on your
site. You do not have to configure your system on UNIX for dynamic IP addressing
because it is set up by default.
If your site is already configured so that the IP address for the computer name is
different from the IP address(es) for the Web sites configured on this server, you can
skip “Setting up maintenance IP addresses” on page 335 and continue with
“Enabling ClusterCATS dynamic IP addressing” on page 337.
Understanding static and dynamic IP address configurations
Each server that you add to a cluster must have an IP address defined for it. Because
the Internet operates on a TCP/IP network protocol for sending and receiving
packets of data to and from networked computers, you must correctly define your
servers’ IP addresses so that they can send and receive network data as intended.
The static address must be assigned to the server itself—the physical box. You do so
by making an entry in the server’s IP stack. On Windows servers, you add this IP
address using the Network icon in the Control Panel.
In addition to assigning the server’s static address, you must make sure that the Web
sites’ static IP addresses that reside on the Web server on this machine get removed
from the IP stack (also via the Network icon in the Control Panel). Typically, you or
someone else added the Web site IP addresses to the server’s IP stack before
installing ClusterCATS and creating clusters. You must now manually remove those
IP addresses so that ClusterCATS can dynamically create them in the IP stack
according to server load and availability in the cluster.
There are generally two ways to move from static to dynamic addressing; one way is
to change the IP address and FQHN of the Web site, and the other method is to
change the address and FQHN of the Web server’s machine. Since most Webmasters
cannot change the web site address, the instructions in this section explain how to
change the computer or machine name.
Note
All computer names associated with the ClusterCATS dynamic IP addresses must
have fully qualified host names (FQHNs) in DNS and DNS forward and reverse
entries.
The general process for configuring ClusterCATS with dynamic IP addressing is as
follows:
1 Set up your servers with maintenance addresses. Refer to “Setting up
maintenance IP addresses” on page 335.
2 Install ClusterCATS.
3 Enable ClusterCATS dynamic IP addressing. Refer to “Enabling ClusterCATS
dynamic IP addressing” on page 337.