Set<Node> getNodes() {
    if (nodes != null) {
      return nodes.getListCopy();
    }
    return null;
  }
Returns a the list of nodes that participate in the PartitionedRegion

@return a copy of the list of nodes that the caller is free to modify
geode-core/src/main/java/org/apache/geode/internal/cache/PartitionRegionConfig.java