Each host must have a server ID unique to the host name. All processes on the same node share the same host-based service ID.
A Kerberos administrator creates a Kerberos service principal name (SPN) for each node in the WebSphere cell. For example, for a cell with three nodes (such as server1.austin.ibm.com, server2.austin.ibm.com and server3.austin.ibm.com), the Kerberos administrator must create the following Kerberos service principals: WAS/server1.austin.ibm.com, WAS/server2.austin.ibm.com, and WAS/server3.austin.ibm.com.
The Kerberos keytab filekrb5.keytab contains all of the SPNs for the node and must be protected. This file can be placed in the config/cells/<cell_name> directory.
Read the Creating a Kerberos principal and keytab article for more information.