public boolean ensureSomeRegionServersAvailable(final int num) throws IOException {
    boolean startedServer = false;
    MiniHBaseCluster hbaseCluster = getMiniHBaseCluster();
    for (int i = hbaseCluster.getLiveRegionServerThreads().size(); i < num; ++i) {
      LOG.info("Started new server=" + hbaseCluster.startRegionServer());
      startedServer = true;
    }

    return startedServer;
  }
Make sure that at least the specified number of region servers are running
@param num minimum number of region servers that should be running
@return true if we started some servers
hbase-testing-util/src/main/java/org/apache/hadoop/hbase/HBaseTestingUtility.java