Failed to get node info error messages

Elastic Stack Elasticsearch
1

We use ES 1.6.0. The system is composed of 35 indices, each with 5 shards and 1 replica.
We get many error messages on the TransportClient log file like this:

[INFO ] [2015-07-22 11:48:11.611] o.e.c.transport               : [Legacy] failed to get node info for [#transport#-1][om-inv][inet[om-inv/192.168.50.200:9300]], disconnecting...
org.elasticsearch.transport.ReceiveTimeoutTransportException: [][inet[om-inv/192.168.50.200:9300]][cluster:monitor/nodes/info] request_id [15675] timed out after [5009ms]
at org.elasticsearch.transport.TransportService$TimeoutHandler.run(TransportService.java:529)
at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1142)
at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:617)
at java.lang.Thread.run(Thread.java:745)

and like this one:

org.elasticsearch.client.transport.NoNodeAvailableException: None of the configured nodes are available: []
at org.elasticsearch.client.transport.TransportClientNodesService.ensureNodesAreAvailable(TransportClientNodesService.java:305)
at org.elasticsearch.client.transport.TransportClientNodesService.execute(TransportClientNodesService.java:200)
at org.elasticsearch.client.transport.support.InternalTransportClient.execute(InternalTransportClient.java:106)
at org.elasticsearch.client.support.AbstractClient.index(AbstractClient.java:102)
at org.elasticsearch.client.transport.TransportClient.index(TransportClient.java:340)
at org.elasticsearch.action.index.IndexRequestBuilder.doExecute(IndexRequestBuilder.java:266)
at org.elasticsearch.action.ActionRequestBuilder.execute(ActionRequestBuilder.java:91)
at org.elasticsearch.action.ActionRequestBuilder.execute(ActionRequestBuilder.java:65)

What is the significance of these and what can be done to fix them?

2

Could you share your modification to elasticsearch.yml? It might have something to do with your http, transport or gateway settings.

3

The only non-commented-out lines in our elasticsearch.yml are:

cluster.name: elasticsearch
node.name: om-inv
plugin.mandatory: head,analysis-icu,analysis-kuromoji,analysis-smartcn,analysis-stempel