public JVMClusterUtil.MasterThread stopMaster(int serverNumber, final boolean shutdownFS) {
    JVMClusterUtil.MasterThread server = hbaseCluster.getMasters().get(serverNumber);
    LOG.info("Stopping " + server.toString());
    server.getMaster().stop("Stopping master " + serverNumber);
    return server;
  }
Shut down the specified master cleanly
@param serverNumber Used as index into a list.
@param shutdownFS   True is we are to shutdown the filesystem as part of this master's
                    shutdown. Usually we do but you do not want to do this if you are running
                    multiple master in a test and you shut down one before end of the test.
@return the master that was stopped
hbase-testing-util/src/main/java/org/apache/hadoop/hbase/MiniHBaseCluster.java