$ docker run -it zappi/filebeat -e -c /etc/filebeat/filebeat.yml -configtest
2017/01/16 03:35:58.581352 beat.go:267: INFO Home path: [/] Config path: [/] Data path: [//data] Logs path: [//logs]
2017/01/16 03:35:58.581395 beat.go:177: INFO Setup Beat: filebeat; Version: 5.1.2
2017/01/16 03:35:58.581419 publish.go:271: INFO No outputs are defined. Please define one under the output section.
2017/01/16 03:35:58.581433 beat.go:288: CRIT Exiting: error initializing publisher: No outputs are defined. Please define one under the output section.
Exiting: error initializing publisher: No outputs are defined. Please define one under the output section.