title: Why are my gunicorn Python/Flask workers exiting from signal term?
body: <p>I have a Python/Flask web application that I am deploying via Gunicorn in a docker image on Amazon ECS. Everything is going fine, and then suddenly, including the last successful request, I see this in the logs:</p>
  
  <p><code>[2017-03-29 21:49:42 +0000] [14] [DEBUG] GET /heatmap_column/e4c53623-2758-4863-af06-91bd002e0107/ADA
  [2017-03-29 21:49:43 +0000] [1] [INFO] Handling signal: term
  [2017-03-29 21:49:43 +0000] [14] [INFO] Worker exiting (pid: 14)
  [2017-03-29 21:49:43 +0000] [8] [INFO] Worker exiting (pid: 8)
  [2017-03-29 21:49:43 +0000] [12] [INFO] Worker exiting (pid: 12)
  [2017-03-29 21:49:43 +0000] [10] [INFO] Worker exiting (pid: 10)
  ...
  [2017-03-29 21:49:43 +0000] [1] [INFO] Shutting down: Master
  </code></p>
  
  <p>And the processes die off and the program exits. ECS then restarts the service, and the docker image is run again, but in the meanwhile the service is interrupted.</p>
  
  <p>What would be causing my program to get a TERM signal? I can't find any references to this happening on the web. Note that this only happens in Docker on ECS, not locally.</p>