code: @Override
      public int syncUp() {
          // Copy entire entry from neighboring DS node
          int count = 0;
  
          for (int i = 0; ((i < serverConfig.getRegistrySyncRetries()) && (count == 0)); i++) {
              if (i > 0) {
                  try {
                      Thread.sleep(serverConfig.getRegistrySyncRetryWaitMs());
                  } catch (InterruptedException e) {
                      logger.warn("Interrupted during registry transfer..");
                      break;
                  }
              }
              Applications apps = eurekaClient.getApplications();
              for (Application app : apps.getRegisteredApplications()) {
                  for (InstanceInfo instance : app.getInstances()) {
                      try {
                          if (isRegisterable(instance)) {
                              register(instance, instance.getLeaseInfo().getDurationInSecs(), true);
                              count++;
                          }
                      } catch (Throwable t) {
                          logger.error("During DS init copy", t);
                      }
                  }
              }
          }
          return count;
      }
docs: Populates the registry information from a peer eureka node. This
  operation fails over to other nodes until the list is exhausted if the
  communication fails.