private String getClusterName(Map<String, Object> propertyMap) {
    String clusterName = (String) propertyMap.get(CLUSTER_KERBEROS_DESCRIPTOR_CLUSTER_NAME_PROPERTY_ID);

    if (StringUtils.isEmpty(clusterName)) {
      throw new IllegalArgumentException("Invalid argument, cluster name is required");
    }

    return clusterName;
  }
Retrieves the cluster name from the request property map.

@param propertyMap the request property map
@return a cluster name
@throws IllegalArgumentException if the cluster name value is missing or empty.
ambari-server/src/main/java/org/apache/ambari/server/controller/internal/ClusterKerberosDescriptorResourceProvider.java