public int getRegionServerInfoPort(final ServerName sn) {
    int port = this.serverManager.getInfoPort(sn);
    return port == 0
      ? conf.getInt(HConstants.REGIONSERVER_INFO_PORT, HConstants.DEFAULT_REGIONSERVER_INFOPORT)
      : port;
  }
Returns timestamp in millis when HMaster finished becoming the active master
hbase-server/src/main/java/org/apache/hadoop/hbase/master/HMaster.java