@After
  public void clear() {
    for (ZkInfo zkInfo : dcsToZkInfo.values()) {
      ZKHelixAdmin admin = new ZKHelixAdmin("localhost:" + zkInfo.getPort());
      admin.dropCluster(CLUSTER_NAME_PREFIX + CLUSTER_NAME_IN_STATIC_CLUSTER_MAP);
    }
  }
Shutdown all Zk servers before exit.
ambry-tools/src/integration-test/java/com/github/ambry/clustermap/HelixBootstrapUpgradeToolTest.java