Open Distro development has moved to OpenSearch. The Open Distro plugins will continue to work with legacy versions of Elasticsearch OSS, but we recommend upgrading to OpenSearch to take advantage of the latest features and improvements.
In order to integrate nmslib’s approximate k-NN functionality, which is implemented in C++, into the k-NN plugin, which is implemented in Java, we created a Java Native Interface library. Check out this wiki to learn more about JNI. This library allows the k-NN plugin to leverage nmslib’s functionality. For more information about how we build the JNI library binary and how to get the most of it in your production environment, see here.