Error: unknown error
    at respond (/var/lib/jenkins/workspace/elastic+kibana+master/kibana/node_modules/elasticsearch/src/lib/transport.js:351:15)
    at checkRespForFailure (/var/lib/jenkins/workspace/elastic+kibana+master/kibana/node_modules/elasticsearch/src/lib/transport.js:306:7)
    at HttpConnector.<anonymous> (/var/lib/jenkins/workspace/elastic+kibana+master/kibana/node_modules/elasticsearch/src/lib/connectors/http.js:173:7)
    at ClientRequest.wrapper (/var/lib/jenkins/workspace/elastic+kibana+master/kibana/node_modules/elasticsearch/node_modules/lodash/lodash.js:4929:19)
    at ClientRequest.emit (events.js:198:13)
    at Socket.socketErrorListener (_http_client.js:401:9)
    at Socket.emit (events.js:198:13)
    at emitErrorNT (internal/streams/destroy.js:91:8)
    at emitErrorAndCloseNT (internal/streams/destroy.js:59:3)
    at process._tickCallback (internal/process/next_tick.js:63:19)