Here's
Filebeat is running and give me the report when i typed filebeat -e -c filebeat.yml or filebeat -e only should be enough. So, i don't follow this step filebeat setup -e on this link https://www.elastic.co/guide/en/beats/filebeat/current/filebeat-module-apache2.html. I think that step is loading the default settings (Kibana, Elasticsearch and Filebeat).
And, the next thread i would make, How could Graylog2 receive input from filebeat harvest ? 
i read forum and i notice GELF can be implemented.