title: Cause of "apiserver received an error that is not an unversioned" errors from kube-apiserver
body: <p>On upgrading kubernetes from 1.0.6 to 1.1.3, I now see a bunch of the below errors during a rolling upgrade when any of my kube master or etcd hosts are down. We currently have a single master, with two etcd hosts.</p>
  
  <pre><code>2015-12-11T19:30:19.061+00:00 kube-master1 [err] [kube-apiserver] E1211 19:30:18.726490   26551 errors.go:62] apiserver received an error that is not an unversioned.Status: too old resource version: 3871210 (3871628)
  2015-12-11T19:30:19.075+00:00 kube-master1 [err] [kube-apiserver] E1211 19:30:18.733331   26551 errors.go:62] apiserver received an error that is not an unversioned.Status: too old resource version: 3871156 (3871628)
  2015-12-11T19:30:19.081+00:00 kube-master1 [err] [kube-apiserver] E1211 19:30:18.736569   26551 errors.go:62] apiserver received an error that is not an unversioned.Status: too old resource version: 3871623 (3871628)
  2015-12-11T19:30:19.095+00:00 kube-master1 [err] [kube-apiserver] E1211 19:30:18.740328   26551 errors.go:62] apiserver received an error that is not an unversioned.Status: too old resource version: 3871622 (3871628)
  2015-12-11T19:30:19.110+00:00 kube-master1 [err] [kube-apiserver] E1211 19:30:18.742972   26551 errors.go:62] apiserver received an error that is not an unversioned.Status: too old resource version: 3871210 (3871628)
  </code></pre>
  
  <p>I believe these errors are caused by <a href="https://github.com/kubernetes/kubernetes/issues/10475" rel="nofollow">this new feature in 1.1</a>, the adding of the --watch-cache option by default. The errors cease at the end of the rolling upgrade.</p>
  
  <p>I would like to know how to explain these errors, if they can be safely ignored, and how to change the system to avoid them in the future (for a longer term solution).</p>