title: DC/OS stateful app with persistent external storage
body: <p>I'm trying to setup a stateful app in DC/OS by assigning an external (EBS) volume to the docker container. I've ran the demo app provided in the docs and it created a 100GB EBS volume in AWS. Is there a way to specify the size of the volume in the <code>marathon.json</code> file? Can I use the same EBS volume for multiple apps? Here's the demo app I've tested.</p>
  
  <pre><code>{
    "id": "/test-docker",
    "instances": 1,
    "cpus": 0.1,
    "mem": 32,
    "cmd": "date &gt;&gt; /data/test-rexray-volume/test.txt; cat /data/test-rexray-volume/test.txt",
    "container": {
      "type": "DOCKER",
      "docker": {
        "image": "alpine:3.1",
        "network": "HOST",
        "forcePullImage": true
      },
      "volumes": [
        {
          "containerPath": "/data/test-rexray-volume",
          "external": {
            "name": "my-test-vol",
            "provider": "dvdi",
            "options": { "dvdi/driver": "rexray" }
          },
          "mode": "RW"
        }
      ]
    },
    "upgradeStrategy": {
      "minimumHealthCapacity": 0,
      "maximumOverCapacity": 0
    }
  }
  </code></pre>