Cluster not responding, weird error message
<p>My container engine cluster has a red exclamation mark next to its name in the Google cloud console overview of the container engine. A tooltip says "<strong>The cluster has a problem. Click the cluster name for details.</strong>" Once I click the name I don't get any more infos, it's just the usual summary.
Stackdriver doesn't report anything unusual. No incidents are logged, all pods are marked as healthy but I can't reach my services.
Trying to get infos or logs via <code>kubectl</code> doesn't work:</p>

<pre><code>kubectl cluster-info
Unable to connect to the server: dial tcp xxx.xxx.xxx.xxx:443: i/o timeout
</code></pre>

<p>How can I debug this problem? And what does this cryptic message mean anyway?</p>