public String getPreconfigureServices() {
    return (kerberosEnvProperties == null) ? "" : kerberosEnvProperties.get(KerberosHelper.PRECONFIGURE_SERVICES);
  }
KerberosDetails is a helper class to hold the details of the relevant Kerberos-specific
configurations so they may be passed around more easily.
ambari-server/src/main/java/org/apache/ambari/server/controller/KerberosDetails.java