Create inference API throws NPE after cluster upgrade: restart master

Create inference API throws NPE after cluster upgrade: restart master

What happened

Issue elastic/elasticsearch#112694 (closed, 26 comments): An error occurred while calling the create inference API in the ES cluster after upgrade. Reporter showed the mappingsversions in GET cluster/state looked right, and restarting the new master made the NPE disappear.

What works

Create inference API throwing an NPE right after a cluster upgrade: root cause is that when the last 8.9 node leaves the cluster, the system index descriptors and their mappings versions are not updated to reflect what is now available. Workaround: restart the master, which forces the update and makes the NPE disappear. Proper fix: upgrade to 8.16.1 (backport PR #116646) or 8.17 (PR #115771), where it is fixed.

Caveats

This comes from one real issue thread (gh:elastic/elasticsearch#112694); it is the verified fix or approach from that thread, not a general manual. Check your version of Elasticsearch first , maintainers often fix the underlying bug in a later release, and the thread may predate it.

Issue gh:elastic/elasticsearch#112694 asked: Issue elastic/elasticsearch#112694 (closed, 26 comments): An error occurred while calling the create inference API in the ES cluster after upgrade. Reporter showed the mappingsversions in GET cluster/state looked right, and restarting the new master made the NPE disappear. The verified answer from the thread: Create inference API throwing an NPE right after a cluster upgrade: root cause is that when the last 8.9 node leaves the cluster, the system index descriptors and their mappings versions are not updated to reflect what is now available. Workaround: restart the master, which forces the update and makes the NPE disappear. Proper fix: upgrade to 8.16.1 (backport PR #116646) or 8.17 (PR #115771), where it is fixed. Source: https://github.com/elastic/elasticsearch/issues/112694