Cant get sandbox_path to work

[Marc Roos]

Don't know how to apply this manual correctly to map a image folder to 
the sandbox.
http://mesos.apache.org/documentation/latest/container-volume/#sandbox_path-volume-source

{
  "id": "/test2",
  "user": "nobody",
  "cpus": 1,
  "mem": 256,
  "disk": 0,
  "instances": 1,
  "acceptedResourceRoles": ["*"],
  "backoffSeconds": 10,
  "networks": [ 
    { "mode": "container", "name": "cni" }
  ],
  "container": {
    "type": "MESOS",
    "docker": {
        "image": "test",
        "credential": null,
        "forcePullImage": true
        },
        "volumes": [
      {
          "mode": "RW",
        "container_path": "/usr/local/tomcat/logs",
          "source": {
         "type": "SANDBOX_PATH",
         "sandbox_path": {
         "type": "SELF",
         "path": "tmp"
         }
      }
      }
      ]
  }
}