digraph {
  compound=true;
  rankdir="LR";

  tag [label="", shape="circle", width=0.1, style="filled", color="black"];
  manifest [shape="note"];
  config [shape="note"];

  tag -> manifest [label="digest", taillabel="tag", tailport=head, labeldistance=2.1, labelangle=108];
  manifest -> config [label="(image id)"];
  config -> l1 [label="diffid"];
  config -> l2 [label="diffid"];
  manifest -> l1 [lhead=cluster_layer1, label="layer digest"];
  manifest -> l2 [lhead=cluster_layer2, label="layer digest"];

  subgraph cluster_layer1 {
    label = "layer.tar.gz";
    margin = 20.0;
    l1 [label="layer.tar", shape="folder"];
  }
  subgraph cluster_layer2 {
    label = "layer.tar.gz";
    margin = 20.0;
    l2 [label="layer.tar", shape="folder"];
  }
}