// Request
POST _security/_ccs/api_key
{
  "name": "k2",
  "role_descriptors": {
    "x": {
      "cluster": [ "cross_cluster_access" ],
      "indices": [
        {
          "names": [ "foo" ],
          "privileges": [ "read", "read_cross_cluster" ]
        }
      ]
    }
  }
}

// Response
{
  "id": "Qq9okocBu0QjU-Ce7i_l",
  "name": "k2",
  "encoded": "ccs_UXE5b2tvY0J1MFFqVS1DZTdpX2w6akIxSmpxZEFSR3E0SFRZek5yekJHZw=="
}