title: Cloud composer tasks fail without reason or logs
body: <p>I run <code>Airflow</code> in a managed <code>Cloud-composer environment</code> (version 1.9.0), whic runs on a <code>Kubernetes</code> 1.10.9-gke.5 cluster.</p>
  
  <p>All my DAGs run daily at 3:00 AM or 4:00 AM. But sometime in the morning, I see a few Tasks failed without a reason during the night.</p>
  
  <ul>
  <li><p>When checking the log using the UI - I see no log and I see no log either when I check the log folder in the GCS bucket <a href="https://i.stack.imgur.com/iQXEH.png" rel="noreferrer"><img src="https://i.stack.imgur.com/iQXEH.png" alt="enter image description here"></a></p></li>
  <li><p>In the instance details, it reads "Dependencies Blocking Task From Getting Scheduled" but the dependency is the dagrun itself. <a href="https://i.stack.imgur.com/CuA48.png" rel="noreferrer"><img src="https://i.stack.imgur.com/CuA48.png" alt="enter image description here"></a></p></li>
  <li><p>Although the DAG is set with 5 retries and an email message it does not look as if any retry took place and I haven't received an email about the failure.</p></li>
  <li><p>I usually just clear the task instance and it run successfully on the first try. </p></li>
  </ul>
  
  <p>Has anyone encountered a similar problem?</p>