* @throws CartridgeAgentException If an error occurs while joining a cluster group
*/
public void joinGroup(Registrant registrant,
ConfigurationContext configurationContext) throws CartridgeAgentException {
if (registrantDatabase.containsActive(registrant)) {
throw new CartridgeAgentException("Active registrant with key " +
registrant.getKey() + " already exists");
}
registrantDatabase.add(registrant);
if (!RegistrantUtil.isHealthy(registrant)) {