/opt/logstash/bin/logstash -f logstash-apache.conf
is not equivalent to systemctl start logstash
even though the only file in /etc/logstash/conf.d is logstash-apache.conf
Please advise.
What do you mean?
Why is it not equivalent?
What do you expect?
Please put more effort into your posts. Not explaining things makes it very hard to provide meaningful assistance. I would encourage you to read https://www.elastic.co/help as well.