public static boolean isCluster(String groupName) {
    return isBlank(groupName) || groupName.equalsIgnoreCase(CLUSTER);
  }
Returns true if the given "groupName" represents the predefined "cluster" group.
This is true if "groupName" is a case-insensitive match for {@link #CLUSTER},
is <code>null</code>, or is an empty string.

@param groupName the group name to be checked
@return true if groupName is a case-insensitive match for {@link #CLUSTER}, is
        <code>null</code>, or is an empty string
geode-management/src/main/java/org/apache/geode/management/configuration/AbstractConfiguration.java