public String abortMaster(int serverNumber) {
    HMaster server = getMaster(serverNumber);
    LOG.info("Aborting " + server.toString());
    server.abort("Aborting for tests", new Exception("Trace info"));
    return server.toString();
  }
Cause a master to exit without shutting down entire cluster.
@param serverNumber Used as index into a list.
hbase-testing-util/src/main/java/org/apache/hadoop/hbase/MiniHBaseCluster.java