protected void startZKNode(ServerName server) throws IOException {
    getLogger().info("Starting zookeeper node {}", server.getHostname());
    cluster.startZkNode(server.getHostname(), server.getPort());
    cluster.waitForZkNodeToStart(server, startZkNodeTimeout);
    getLogger().info("Started zookeeper node {}", server);
  }
Returns current region servers - active master
hbase-it/src/test/java/org/apache/hadoop/hbase/chaos/actions/Action.java