private static void setupHDFSProxyUsers(Configuration configuration, Set<String> configTypesUpdated, Collection<String> services) {
    if (services.contains("HDFS")) {
      Set<Pair<String, String>> configTypePropertyPairs = generateHadoopProxyUserPropertyNames(configuration);
      Set<String> acceptableConfigTypes = getEligibleConfigTypesForHadoopProxyUsers(services);

      Map<String, Map<String, String>> existingProperties = configuration.getFullProperties();
      for (Pair<String, String> pair : configTypePropertyPairs) {
        String configType = pair.getLeft();
        if (acceptableConfigTypes.contains(configType)) {
          Map<String, String> configs = existingProperties.get(configType);
          if (configs != null) {
            ensureProperty(configuration, "core-site", pair.getRight(), "*", configTypesUpdated);
          }
        }
      }
    }
  }
Ensures {@code hadoop.proxyuser.*} properties are present in core-site for the services defined in the blueprint.
ambari-server/src/main/java/org/apache/ambari/server/controller/internal/BlueprintConfigurationProcessor.java