Causing document not indexed

Elastic Stack Elasticsearch
1

In my bulk index log, I saw this:

Oct 10 2016 12:11:53.113 [elasticsearch[Deathstroke][generic][T#6] ] INFO org.elasticsearch.client.transport - [Deathstroke] failed to get local cluster state for {ip-10-4-42-137}{nwchmGSOSFStn5Nyl3RUZQ}{10.4.42.137}{10.4.42.137:9300}, disconnecting...
org.elasticsearch.transport.ReceiveTimeoutTransportException: [ip-10-4-42-137][10.4.42.137:9300][cluster:monitor/state] request_id [365] timed out after [5001ms]
at org.elasticsearch.transport.TransportService$TimeoutHandler.run(TransportService.java:696)
at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1142)
at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:617)
at java.lang.Thread.run(Thread.java:745)

The document count I submitted are different from what is in index.

Is possible that this is causing documents not written to index? Any idea what caused this and how to solve it?

2

I am still seeing the same issue. wondering if anybody seen this during bulk index;

I google online and somebody mentioned that sniff might cause this issue; so I directly connect to the servers and turn off sniff; but still see 2 times of this exception during my 4 hours indexing process; and some documents are missing; I don't see any other exception issue;