title: Strange behavior when using Marathon Health Check with the command protocol and a container
body: <p>I can't figure out why the following request won't start health checking in Marathon. The container is started but the status remains <code>Deploying</code></p>
  
  <pre><code>{
    "id": "bridged-webapp",
    "cmd": "python3 -m http.server 8080",
    "cpus": 0.1,
    "mem": 64.0,
    "instances": 1,
    "container": {
       "type": "DOCKER",
       "docker": {
         "image": "python:3",
          "network": "BRIDGE",
          "portMappings": [
             { 
               "containerPort": 8080,
               "hostPort": 31313,
               "servicePort": 9000,
               "protocol": "tcp"
             }
          ]
        }
      },
    "healthChecks": [
      {
          "protocol": "COMMAND",
          "command": { "value": "echo 0" },
          "maxConsecutiveFailures": 3
      }
     ]
  }
  </code></pre>
  
  <p>When I look at the logs of Marathon it basically just says that Health check has started but nothing more :</p>
  
  <pre><code>Aug 28 16:52:33 cnode2 marathon[11495]: [2015-08-28 16:52:33,603] INFO   Adding health check for app [/bridged-webapp] and version [2015-08-28T16:52:33.500Z]: [HealthCheck(Some(/),COMMAND,0,Some(Command(echo 0)),300 seconds,60 seconds,20 seconds,3,false)] (mesosphere.marathon.health.MarathonHealthCheckManager$$EnhancerByGuice$$d8828133:76)
  Aug 28 16:52:33 cnode2 marathon[11495]: [INFO] [08/28/2015 16:52:33.604] [marathon-akka.actor.default-dispatcher-693] [akka://marathon/user/$kg] Starting health check actor for app [/bridged-webapp] and healthCheck [HealthCheck(Some(/),COMMAND,0,Some(Command(echo 0)),300 seconds,60 seconds,20 seconds,3,false)]
  Aug 28 16:52:33 cnode2 marathon[11495]: [INFO] [08/28/2015 16:52:33.627] [marathon-akka.actor.default-dispatcher-694] [akka://marathon/user/MarathonScheduler/$a/DeploymentManager/4f3a1a8e-8934-441a-9c55-b7cf332893e2/$a] Successfully started 0 instances of /bridged-webapp
  Aug 28 16:52:37 cnode2 marathon[11495]: [2015-08-28 16:52:37,080] INFO Received status update for task bridged-webapp.2f4399a5-4da5-11e5-b538-080027bb2503: TASK_RUNNING () (mesosphere.marathon.MarathonScheduler$$EnhancerByGuice$$b7a64e04:100)
  </code></pre>
  
  <p>In the UI the job health is gray meaning that Health checking is unknown.</p>
  
  <p>What is really strange is that if I run the same job but without the container it works.</p>
  
  <p>Any ideas ?</p>