title: kubernetes error syncing pod - how to debug
body: <p>I often get errors about pods not syncing / ImagePullBackOff errors on my Kubernetes cluster on Google Kubernetes Engine.  But I'm not sure how to debug the issue as I can't establish the root cause.</p>
  
  <p>In the Google dashboard I can see the ReplicaSet has the warning:
  Pod errors: ImagePullBackOff</p>
  
  <p>If I drill down to the pod, I can see in the logs:
  Message: Error syncing pod
  Reason: FailedSync</p>
  
  <p><a href="https://i.stack.imgur.com/d1Cll.png" rel="noreferrer"><img src="https://i.stack.imgur.com/d1Cll.png" alt="enter image description here"></a></p>
  
  <p>but nothing further.  Why would a pod fail to sync?</p>
  
  <p>UPDATE: further down in the logs I see:</p>
  
  <pre><code>Failed to pull image "cockroachdb/cockroach:v1.1.3": rpc error: code = Unknown desc = failed to register layer: ApplyLayer exit status 1 stdout: stderr: open /usr/share/zoneinfo/right/America/Pangnirtung: no space left on device
  </code></pre>
  
  <p>I've allocated cockroachdb 1 GB of persistent storage - going to try to increase to 10 GB to see if that fixes anything.  Or do I need to increase the disk size on the node pools?</p>