@Override
  public ShutdownResponse shutdown(RpcController controller, ShutdownRequest request)
    throws ServiceException {
    LOG.info(server.getClientIdAuditPrefix() + " shutdown");
    try {
      server.shutdown();
    } catch (IOException e) {
      LOG.error("Exception occurred in HMaster.shutdown()", e);
      throw new ServiceException(e);
    }
    return ShutdownResponse.newBuilder().build();
  }
Turn on/off snapshot auto-cleanup based on TTL
@param enabledNewVal Set to <code>true</code> to enable, <code>false</code> to disable
@param synchronous   If <code>true</code>, it waits until current snapshot cleanup is
                     completed, if outstanding
@return previous snapshot auto-cleanup mode
hbase-server/src/main/java/org/apache/hadoop/hbase/master/MasterRpcServices.java