Updating the /etc/hosts file and name server configuration
Make sure all nodes can resolve all cluster addresses.
Edit the /etc/hosts file (and the /etc/resolv.conf file, if using the name server configuration) on each node in the cluster to make sure the IP addresses of all clustered interfaces are listed.
For each PowerHA® SystemMirror® service
and boot IP label, make an entry similar to the following:
100.100.50.200 payroll-service
Also, make sure that the /etc/hosts file on each node has the following entry:
127.0.0.1 loopback localhost