public List<String> getRollingUpgradeSkipPackagesPrefixes() {
    String propertyValue = getProperty(ROLLING_UPGRADE_SKIP_PACKAGES_PREFIXES);
    ArrayList<String> res = new ArrayList<>();
    for (String prefix : propertyValue.split(",")) {
      if (! prefix.isEmpty()) {
        res.add(prefix.trim());
      }
    }
    return res;
  }
@return a list of prefixes. Packages whose name starts with any of these
prefixes, should be skipped during upgrade.
ambari-server/src/main/java/org/apache/ambari/server/configuration/Configuration.java