private void createRunDir() throws IOException {
    if (!bootDir.exists()) {
      // create the bootdir directory.
      if (! bootDir.mkdirs()) {
        throw new IOException("Cannot create " + bootDir);
      }
    }
    /* create the request id directory */
    if (requestIdDir.exists()) {
      /* delete the directory and make sure we start back */
      FileUtils.deleteDirectory(requestIdDir);
    }
    /* create the directory for the run dir */
    if (! requestIdDir.mkdirs()) {
      throw new IOException("Cannot create " + requestIdDir);
    }
  }
Create request id dir for each bootstrap call *
ambari-server/src/main/java/org/apache/ambari/server/bootstrap/BSRunner.java