Managing Serviceguard 12th Edition, March 2006

Building an HA Cluster Configuration
Managing the Running Cluster
Chapter 5 265
NOTE The /sbin/init.d/cmcluster file may call files that Serviceguard
stored in the directories: /etc/cmcluster/rc (HP-UX) and
${SGCONF}/rc (Linux). The directory is for Serviceguard use only! Do not
move, delete, modify, or add files to this directory.
Changing the System Message
You may find it useful to modify the system's login message to include a
statement such as the following:
This system is a node in a high availability cluster.
Halting this system may cause applications and services to
start up on another node in the cluster.
You might wish to include a list of all cluster nodes in this message,
together with additional cluster-specific information.
The /etc/issue and /etc/motd files may be customized to include
cluster-related information.
Managing a Single-Node Cluster
The number of nodes you will need for your Serviceguard cluster depends
on the processing requirements of the applications you want to protect.
You may want to configure a single-node cluster to take advantage of
Serviceguard’s network failure protection.
In a single-node cluster, a cluster lock is not required, since there is no
other node in the cluster. The output from the cmquerycl command
omits the cluster lock information area if there is only one node.
You still need to have redundant networks, but you do not need to specify
any heartbeat LANs, since there is no other node to send heartbeats to.
In the cluster configuration ASCII file, specify all LANs that you want
Serviceguard to monitor. For LANs that already have IP addresses,
specify them with the STATIONARY_IP keyword, rather than the
HEARTBEAT_IP keyword. For standby LANs, all that is required is the
NETWORK_INTERFACE keyword with the LAN device name.