User Guide

ClusterCATS Dynamic IP Addressing (Windows only) 335
4 Create your clusters. “Creating clusters in Windows” on page 252.
Benefits of ClusterCATS dynamic IP addressing
There are several benefits to using ClusterCATS dynamic IP addressing:
• Using Maintenance mode. With dynamic IP addressing, cluster members put
into Maintenance mode on Windows clusters will fail over to another server and
then gracefully return when brought out of Maintenance mode. For more
information on Maintenance mode, refer to “Using Maintenance Mode
(Windows only)” on page 313.
• Using maintenance IP addresses. If you use ClusterCATS dynamic IP addressing,
you can remotely access servers in your cluster if they fail or become unavailable
through the maintenance address. Maintenance addresses are statically bound to
the server during the setup for ClusterCATS dynamic IP addressing. For more
information on using maintenance addresses, refer to “Setting up maintenance
IP addresses” on page 335.
• Optimizing Server failover. On Windows systems, when ClusterCATS is
configured using static IP addresses, IP address conflicts will occur when the
failed server recovers from a failover and tries to re-claim its IP address. This IP
conflict is cleared when the failed server automatically reboots. ClusterCATS
Dynamic IP Addressing prevents this double-reboot.
Setting up maintenance IP addresses
Setting up a maintenance IP address ensures that you have one static IP address on
the system that is not assigned to any Web server, virtual server, or Web site. This
static address, often referred to as the system’s “maintenance address,” provides
administrators with a consistent way to access the system remotely at all times. It
also allows ClusterCATS to be able to communicate with the server in the event of a
Web server failure.
Note
You must have at least two IP addresses available for a machine in order to use one
for a maintenance IP address.
This section shows you how to add a maintenance address that will support
ClusterCATS dynamic IP addressing. If your server has only one static address that
corresponds to both the computer name and the Web site, you must reconfigure it to
allow for a maintenance address.
Note
This procedure must be performed on each system in the cluster and must be done
before installing ClusterCATS.