[NodeJS] Error socket hang up, No Living connections

[lfallet (Laurent)]

Elasticsearch version : 6.4.3, deployed in ElasticCloud
Elasticsearch Node package version : 15.2.0

We're experiencing recurring errors:

Elasticsearch ERROR: 2019-02-26T13:31:11Z
  Error: Request error, retrying
  POST https://xxx.gcp.cloud.es.io:9243/a_comment/comment/_search => socket hang up
      at Log.error (/app/node_modules/elasticsearch/src/lib/log.js:226:56)
      at checkRespForFailure (/app/node_modules/elasticsearch/src/lib/transport.js:259:18)
      at HttpConnector.<anonymous> (/app/node_modules/elasticsearch/src/lib/connectors/http.js:163:7)
      at ClientRequest.wrapper (/app/node_modules/lodash/lodash.js:4935:19)
      at emitOne (events.js:121:20)
      at ClientRequest.emit (events.js:211:7)
      at TLSSocket.socketOnEnd (_http_client.js:423:9)
      at emitNone (events.js:111:20)
      at TLSSocket.emit (events.js:208:7)
      at endReadableNT (_stream_readable.js:1064:12)
      at _combinedTickCallback (internal/process/next_tick.js:138:11)
      at process._tickCallback (internal/process/next_tick.js:180:9)

 warn: [ESService.find] No Living connections
error: [CommentService.find] No Living connections

Are those error usual?
Is retrying a normal process with a decently sized cluster (3 nodes, 8Gb RAM for less than 5000 documents indexed) ?
Is there a specific configuration for NodeJS 8 ?
How could I investigate about the pool, how old connections are?

Regards,
Laurent

[dadoonet (David Pilato)]

@spalger Do you think you can help here?