@Override
  public void start() throws Exception {
    final Policy.PolicyContext context = new Policy.PolicyContext(monkeyProps, util);
    for (final Policy policy : policies) {
      policy.init(context);
      monkeyThreadPool.execute(policy);
    }
  }
Selects and returns ceil(ratio * items.length) random items from the given array
hbase-it/src/test/java/org/apache/hadoop/hbase/chaos/monkies/PolicyBasedChaosMonkey.java