You must have all the required IP addresses and hostnames before you begin the installation process. The logical hostname is a special high availability (HA) resource. The Sun Cluster Geographic Edition software requires that the hostname of a logical host is identical to the cluster name.
You must set up a number of IP addresses for various Sun Cluster Geographic Edition components, depending on your cluster configuration. Each node in the cluster configuration must have at least one public-network connection to the same set of public subnets.
See IP Addresses in Sun Cluster Software Installation Guide for Solaris OS for a list of components that require IP addresses. Add these IP addresses to any naming services that are used. Also add these IP addresses to the local /etc/inet/hosts file on each cluster node after you install Solaris software.