RockNSM 2.1 dropped the day before ES 6.4 was released. This is a placeholder for any issues that come up and the necessary fixes (hopefully) to get and keep you going until we’re all sync’ed up again.
The logstash kafka plugin bundled with 6.4 has a regression. To get it back up and running you just need to update the plugin:
sudo bin/logstash-plugin uninstall logstash-output-kafka sudo bin/logstash-plugin install --version 7.1.3 logstash-output-kafka