I don't use Kerberos, but I'm sure some other folks around here could help you with your query.

Anyone?

Hi krishna

When configuring kerberos, you will need to have SETSPNs for all servers in the cluster (including Backup primary servers), and any load balancers or reverse proxies.

See following

Configure Kerberos

As the backup primary server isn't actually part of the cluster, you are going to have to edit the Kerberos Configuration Script and add it.

At the point of failover to the backup primary server, no additional changes should need to be made

All the best

Glen