You must determine the file location for Installing the Kerberos Keys on database nodes and on each Unity server (if used), and then use the location when setting of the value of the TeradataKeyTab property. See TeradataKeyTab.
The value of TeradataKeyTab in the KRB5 mechanism affects all Kerberos authentication, including logons that use the SPNEGO mechanism.
The default value for the TeradataKeyTab property is /etc/teradata.keytab. Use this default location unless there is a reason to not do so. If you need to use a custom install location due to site policy requirements, you must also change the value of the TeradataKeyTab property to match the custom location.
The Linux user under which Teradata Vantage and Unity run must have read access to the keytab file. If you specify a custom (non-default) file location, you must grant read access permission for the file to the Linux user.