code: private static List<InetSocketAddress> getAvatarNodeAddresses(String suffix,
        Configuration conf, Collection<String> serviceIds) throws IOException{
      List<InetSocketAddress> namenodeAddresses = DFSUtil.getRPCAddresses(suffix,
          conf, serviceIds, FSConstants.DFS_NAMENODE_RPC_ADDRESS_KEY);
      List<InetSocketAddress> avatarnodeAddresses = 
        new ArrayList<InetSocketAddress>(namenodeAddresses.size());
      for (InetSocketAddress namenodeAddress : namenodeAddresses) {
        avatarnodeAddresses.add(
            new InetSocketAddress(namenodeAddress.getAddress(), conf.getInt(
                "dfs.avatarnode.port", namenodeAddress.getPort() + 1)));
      }
      return avatarnodeAddresses;
    }
docs: Returns the IP:port address of the avatar node