If you chose to enable Kerberos using the Automated Kerberos Setup
option, as part of the enabling Kerberos process, Ambari installs the
Kerberos clients on the cluster hosts.
If your Cluster is already kerberized then you do not need to do anything special after adding the new node to it. Whatever components you will install to that newly added host ambari will make sure to add the kerberized configurations to it. Ambari should install the Kerberos client on that after adding the host , You can simply click on "Install Clients" on the "Hosts" page of the newly added host.