@RestrictedApi(explanation = "Should only be called in tests", link = "",
      allowedOnPath = ".*(/src/test/.*|StochasticLoadBalancer).java")
  Pair<CandidateGenerator, BalanceAction> nextAction(BalancerClusterState cluster) {
    CandidateGenerator generator = getRandomGenerator(cluster);
    return Pair.newPair(generator, generator.generate(cluster));
  }
Update the number of metrics that are reported to JMX
hbase-balancer/src/main/java/org/apache/hadoop/hbase/master/balancer/StochasticLoadBalancer.java