private VersionDefinitionXml timedVDFLoad(URI uri) throws Exception {
    long time = System.currentTimeMillis();

    try {
      return VersionDefinitionXml.load(uri.toURL());
    } finally {
      LOG.info("Loaded VDF {} in {}ms", uri, System.currentTimeMillis() - time);
    }

  }
Resolves a base url given that certain OS types can be used interchangeably.
@param os the target os to find
@param osMap the map of os-to-baseurl
@return the url for an os.
ambari-server/src/main/java/org/apache/ambari/server/state/stack/LatestRepoCallable.java