VB I am using this presently. After some trial and tribulations it seems to be fairing pretty well. Though, more complex search capabilities would be appreciated!
Do note that the API URL in the module must be formatted as "<HTTP Protocol>://<ElasticSearch IP>:<Specified Query/Ingest Port>". You cannot have an ending / in the API URL. An example is "https://localhost:9200". Note, installing ElasticSearch on the same VM/dedicated box as UNA is a bit counter productive. It is best to turn up ElasticSearch on a dedicated VM/box. I went on and built a 4 node cluster for resiliency and performance as the UNA install grows. But, it is also ingesting server log data without a blip.
For those that are worried about IP space, you should be able to use RFC1918 space. I just happen to have a fairly large allocation of IPv6 and utilized that for back office systems. There's no issue utilizing IPv6! However, do be careful and ensure your hosts are behind firewalls. You wouldn't want these exposed anymore than necessary!