private void addStateModelDef() {
    for (Map.Entry<String, HelixAdmin> entry : adminForDc.entrySet()) {
      // Add a cluster entry in every enabled DC
      String dcName = entry.getKey();
      HelixAdmin admin = entry.getValue();
      if (!isClusterPresent(dcName)) {
        throw new IllegalStateException("Cluster " + clusterName + " in " + dcName + " doesn't exist!");
      }
      if (!admin.getStateModelDefs(clusterName).contains(stateModelDef)) {
        info("Adding state model def {} in {} for cluster {}", stateModelDef, dcName, clusterName);
        admin.addStateModelDef(clusterName, stateModelDef, getStateModelDefinition(stateModelDef));
      } else {
        info("{} in {} already has state model def {}, skip adding operation", clusterName, dcName, stateModelDef);
      }
    }
  }
Add new state model def to ambry cluster in enabled datacenter(s).
ambry-clustermap/src/main/java/com/github/ambry/clustermap/HelixBootstrapUpgradeUtil.java