I have just enable metricbeat.
using very simple config.
metricbeat.config.modules:
  path: ${path.config}/modules.d/*.yml
  reload.enabled: false
setup.template.settings:
  index.number_of_shards: 1
  index.codec: best_compression
setup.dashboards.enabled: true
setup.kibana:
  host: "http://localhost:5601"
output.elasticsearch:
  hosts: ["localhost:9200"]
I have only enable system.yml in /etc/metricbeat/module.d/ directoy.
I got lot of fields in my index. like kubernetes., postgresql., docker*, It has total 3625 field listed in metricbeat* index pattern.
where are they coming from? my system do not even have any kubernetes installed or running.