apollo-portal/src/main/java/com/ctrip/framework/apollo/portal/controller/ClusterController.java/ClusterController/createCluster
class ClusterController:  @PreAuthorize(value = "@permissionValidator.hasCreateClusterPermission(#appId)")
  @PostMapping(value = "apps/{appId}/envs/{env}/clusters")
  public ClusterDTO createCluster(@PathVariable String appId, @PathVariable String env,
                                  @Valid @RequestBody ClusterDTO cluster) {
    String operator = userInfoHolder.getUser().getUserId();
    cluster.setDataChangeLastModifiedBy(operator);
    cluster.setDataChangeCreatedBy(operator);

    return clusterService.createCluster(Env.valueOf(env), cluster);
  }