title: Pods not moved on host failure
body: <p>i have setup myself a simple 1 master and 3 nodes setup running on Ubuntu based on the book "Kuberenetes Up &amp; Running" in combination with the official documentation.</p>
  
  <p>It basically works until i shutdown one of the <code>worker</code> nodes.
  After a few seconds the nodes-running-state switches to <code>unknown</code>.
  The pods keep report the state <code>running</code> even if the pods are located on the offline node.</p>
  
  <p>Shouldn't k8s move these pods to a different healthy host? 
  Am i missing something?</p>
  
  <p>thanks in advice!</p>