By enabling the trace, I now see the following as the root cause.
**"error": "Content-Type header [application/x-ldjson] is not supported",**
** "status": 406**
This happens in bulk indexing while index.js parsing the items from data.json file and trying to index as a bulk.
I see a change log from elasticsearch says following
_13.0.0 (Apr 24 2017)_
_bulk and other APIs that send line-delimited JSON bodies now use the Content-Type: application/x-ndjson header #507_
Any idea how to resolve this content type issue in index.js?