title: Log flood after master upgrade from 1.6.13-gke.0 to 1.7.11-gke.1
body: <p>We have a GKE cluster with:</p>
  
  <ul>
  <li>master nodes with version 1.6.13-gke.0</li>
  <li>2 node pools with version 1.6.11-gke.0</li>
  </ul>
  
  <p>We have Stackdriver Monitoring and Logging activated.</p>
  
  <p>On 2018-01-22, masters where upgraded by Google to version 1.7.11-gke.1.</p>
  
  <p>After this upgrade, we have a lot of errors like these:</p>
  
  <pre><code>I  2018-01-25 11:35:23 +0000 [error]: Exception emitting record: No such file or directory @ sys_fail2 - (/var/log/fluentd-buffers/kubernetes.system.buffer..b5638802e3e04e72f.log, /var/log/fluentd-buffers/kubernetes.system.buffer..q5638802e3e04e72f.log)
  
  I  2018-01-25 11:35:23 +0000 [warn]: emit transaction failed: error_class=Errno::ENOENT error="No such file or directory @ sys_fail2 - (/var/log/fluentd-buffers/kubernetes.system.buffer..b5638802e3e04e72f.log, /var/log/fluentd-buffers/kubernetes.system.buffer..q5638802e3e04e72f.log)" tag="docker"
  
  I    2018-01-25 11:35:23 +0000 [warn]: suppressed same stacktrace
  </code></pre>
  
  <p>Those messages are flooding our logs ~ 25Gb of logs each day, and are generated by pods managed by a DaemonSet called fluentd-gcp-v2.0.9 .</p>
  
  <p>We found that it's a <a href="https://github.com/kubernetes/kubernetes/issues/56653" rel="nofollow noreferrer">bug</a> fixed on 1.8 and <a href="https://github.com/kubernetes/kubernetes/pull/57048" rel="nofollow noreferrer">backported to 1.7.12</a>.</p>
  
  <p>My questions are:</p>
  
  <ol>
  <li>Should we upgrade masters to version 1.7.12 ? Is it safe to do it? OR</li>
  <li>Is there any other alternative to test before upgrading?</li>
  </ol>
  
  <p>Thanks in advance.</p>