private int startLlap(Path tmpDir, Path scriptParent) throws IOException, InterruptedException {
    int rc;
    String version = System.getenv("HIVE_VERSION");
    if (StringUtils.isEmpty(version)) {
      version = DateTimeFormatter.BASIC_ISO_DATE.format(LocalDateTime.now());
    }

    String outputDir = cl.getOutput();
    Path packageDir = null;
    if (outputDir == null) {
      outputDir = OUTPUT_DIR_PREFIX + version;
      packageDir = new Path(Paths.get(".").toAbsolutePath().toString(), OUTPUT_DIR_PREFIX + version);
    } else {
      packageDir = new Path(outputDir);
    }

    rc = runPackagePy(tmpDir, scriptParent, version, outputDir);
    if (rc == 0) {
      String tarballName = cl.getName() + "-" + version + ".tar.gz";
      startCluster(conf, cl.getName(), tarballName, packageDir, conf.getVar(ConfVars.LLAP_DAEMON_QUEUE_NAME));
    }
    return rc;
  }
This is a working configuration for the instance to merge various variables.
It is not written out for llap server usage
llap-server/src/java/org/apache/hadoop/hive/llap/cli/service/LlapServiceDriver.java