Most minimal logstash.yml possible?

Elastic Stack Logstash
1

I would like to load all my inputs via the conf.d folder.

What is most minimal logstash.yml fle I can have that will allow logstash to start and then load all the yml files in the conf.d folder?

Current logstash.yml file

azureuser@kafka-elk-lab3:~$ sudo cat /etc/logstash/logstash.yml
input {
  kafka {
    bootstrap_servers => "localhost:9092"
    topics => "apache"
    }
}
filter {
    grok {
      match => { "message" => "%{COMBINEDAPACHELOG}" }
    }
    date {
    match => [ "timestamp" , "dd/MMM/yyyy:HH:mm:ss Z" ]
    }
  geoip {
      source => "clientip"
      target => "clientgeo"
    }
}
output {
  elasticsearch {
    hosts => ["localhost:9200"]
  }
}
2

You should put that in logstash.conf or anything named with .conf.
The logstash.yml contains LS settings related to LS execution. Read here.