code: public static Map<String, List<String>> getZoneBasedDiscoveryUrlsFromRegion(EurekaClientConfig clientConfig, String region) {
          String discoveryDnsName = null;
          try {
              discoveryDnsName = "txt." + region + "." + clientConfig.getEurekaServerDNSName();
  
              logger.debug("The region url to be looked up is {} :", discoveryDnsName);
              Set<String> zoneCnamesForRegion = new TreeSet<String>(DnsResolver.getCNamesFromTxtRecord(discoveryDnsName));
              Map<String, List<String>> zoneCnameMapForRegion = new TreeMap<String, List<String>>();
              for (String zoneCname : zoneCnamesForRegion) {
                  String zone = null;
                  if (isEC2Url(zoneCname)) {
                      throw new RuntimeException(
                              "Cannot find the right DNS entry for "
                                      + discoveryDnsName
                                      + ". "
                                      + "Expected mapping of the format <aws_zone>.<domain_name>");
                  } else {
                      String[] cnameTokens = zoneCname.split("\\.");
                      zone = cnameTokens[0];
                      logger.debug("The zoneName mapped to region {} is {}", region, zone);
                  }
                  List<String> zoneCnamesSet = zoneCnameMapForRegion.get(zone);
                  if (zoneCnamesSet == null) {
                      zoneCnamesSet = new ArrayList<String>();
                      zoneCnameMapForRegion.put(zone, zoneCnamesSet);
                  }
                  zoneCnamesSet.add(zoneCname);
              }
              return zoneCnameMapForRegion;
          } catch (Throwable e) {
              throw new RuntimeException("Cannot get cnames bound to the region:" + discoveryDnsName, e);
          }
      }
docs: Get the zone based CNAMES that are bound to a region.
  
  @param region
  - The region for which the zone names need to be retrieved
  @return - The list of CNAMES from which the zone-related information can
  be retrieved