Machine learning features unavailable after rolling upgradeedit

This problem occurs after you upgrade all of the nodes in your cluster to 8.0.0-alpha1 by using rolling upgrades. When you try to use machine learning features for the first time, all attempts fail, though GET _xpack and GET _xpack/usage indicate that X-Pack is enabled.

Symptoms:

  • Errors when you click Machine Learning in Kibana. For example: Jobs list could not be created and An internal server error occurred.
  • Null pointer and remote transport exceptions when you run machine learning APIs such as GET _ml/anomaly_detectors and GET _ml/datafeeds.
  • Errors in the log files on the master nodes. For example: unable to install ml metadata upon startup

Resolution:

After you upgrade all master-eligible nodes to Elasticsearch 8.0.0-alpha1, restart the current master node, which triggers the machine learning features to re-initialize.

For more information, see Rolling upgrades.