protected JSONObject makeJsonPartitionLayout(String partitionClass) throws JSONException {
      version = defaultVersion;
      jsonPartitions =
          getJsonPartitions(partitionCount, partitionClass, partitionState, replicaCapacityInBytes, replicaCountPerDc,
              testHardwareLayout, basePartitionId);
      return getJsonPartitionLayout(testHardwareLayout.getHardwareLayout().getClusterName(), version, partitionCount,
          jsonPartitions);
    }
Get given number of datanodes from each datacenter.
@param dataNodeCountPerDc number of datanodes to get from each datacenter.
@return a list of datanodes.
ambry-clustermap/src/test/java/com/github/ambry/clustermap/TestUtils.java