Logstash 5.0.0-alpha4 has been released yesterday with a good deal of new features and the Monitoring API has been beefed up quite a bit. The previous version of logstashbeat used to gather events, jvm and process node stats.
With the release of 5.0.0-alpha4, memory node stats are now also available and logstashbeat gathers them as well from your running Logstash-5.0.0-alpha4 instance and ships them to Elasticsearch (see sample document).
Check out the latest release of logstashbeat at: https://github.com/consulthys/logstashbeat
Another version to gather pipeline stats and hot threads stats is also in the works.
Stay tuned...