public boolean isContainer() {
    return false;
  }
Test this AbstractKerberosDescriptor to see if it is a container.
<p/>
The default implementation always returns false.  Implementing classes should override this
method to return something different, like true.

@return true if this AbstractKerberosDescriptor is a container, false otherwise
ambari-server/src/main/java/org/apache/ambari/server/state/kerberos/AbstractKerberosDescriptor.java