If the domain is used for testing or development and does not require a high level of security, you can set the service principal at the node level. You can use one SPN and keytab file for the node and all the service processes on the node. When you create additional services on a node, you do not need to create additional keytab files.
If the domain is used for production and requires a high level of security, you can set the service principal at the process level. Create a unique SPN and keytab file for each node and each process on the node. The number of SPNs and keytab files required for each node depends on the number of service processes that run on the node.