Managing Serviceguard 14th Edition, June 2007

Building an HA Cluster Configuration
Preparing Your Systems
Chapter 5210
NOTE HP also recommends that you make DNS highly available, either by
using multiple DNS servers or by configuring DNS into a Serviceguard
package.
Safeguarding against Loss of Name Resolution Services
This section explains how to create a robust name-resolution
configuration that will allow cluster nodes to continue communicating
with one another if DNS or NIS services fail. If a standby LAN is
configured, this approach also allows the cluster to continue to function
fully (including commands such as cmrunnode and cmruncl) after the
primary LAN has failed.
NOTE If a NIC fails, the affected node will be able to fail over to a standby LAN
so long as the node is running in the cluster. But if a NIC that is used by
Serviceguard fails when the affected node is not running in the cluster,
Serviceguard will not be able to restart the node. (For instructions on
replacing a failed NIC, see “Replacing LAN or Fibre Channel Cards” on
page 398.)
1. Edit the /etc/hosts file on all nodes in the cluster. Add name
resolution for all heartbeat IP addresses, and other IP addresses
from all the cluster nodes; see “Configuring IP Address Resolution”
on page 202 for discussion and examples.
NOTE For each cluster node, the public-network IP address must be the
first address listed. This enables other applications to talk to other
nodes on public networks.
2. If you are using DNS, make sure your nameservers are configured in
/etc/resolv.conf, for example:
domain cup.hp.com
search cup.hp.com hp.com
nameserver 15.243.128.51