Once a model is up and running, you can track some basic logs and statistics on the model's Monitoring page.

In case issues arise:
  • Check that you are handling bad input from users. If your function throws an exception, Cloudera Data Science Workbench will restart your model to attempt to get back to a known good state. The user will see an unexpected model shutdown error.

    For most transient issues, model replicas will respond by restarting on their own before they actually crash. This auto-restart behavior should help keep the model online as you attempt to debug runtime issues.

  • Make runtime troubleshooting easier by printing errors and output to stderr and stdout. You can catch these on each model's Monitoring tab. Be careful not to log sensitive data here.

  • The Monitoring tab also displays the status of each replica and will show if the replica cannot be scheduled due to a lack of cluster resources. It will also display how many requests have been served/dropped by each replica.

    When Cloudera Data Science Workbench receives a call request for a model, it attempts to find a free replica that can answer the call. If the first arbitrarily selected replica is busy, Cloudera Data Science Workbench will keep trying to contact a free replica for 30 seconds. If no replica is available, Cloudera Data Science Workbench will return a model.busy error with HTTP status code 429 (Too Many Requests). If you see such errors, re-deploy the model build with a higher number of replicas.