Here is the process:
sudo service logstash start
sudo service logstash status
logstash.service - logstash
Loaded: loaded (/etc/systemd/system/logstash.service; disabled; vendor preset : disabled)
Active: **active** (running) since Fri 2020-09-04 13:43:05 IST; 8s ago
sudo service elasticsearch start
Starting elasticsearch (via systemctl): [ OK ]
sudo service elasticsearch status
elasticsearch.service - Elasticsearch
Loaded: loaded (/usr/lib/systemd/system/elasticsearch.service; disabled; vendor preset: disabled)
Drop-In: /etc/systemd/system/elasticsearch.service.d
└─startup-timeout.conf
Active: **active** (running)
sudo service logstash status
logstash.service - logstash
Loaded: loaded (/etc/systemd/system/logstash.service; disabled; vendor preset: disabled)
Active: failed (Result: start-limit) since Fri 2020-09-04 13:46:24 IST; 1min 11s ago
Process: xxxxx ExecStart=/usr/share/logstash/bin/logstash --path.settings /etc/logstash (code=exited, status=1/FAILURE)
Main PID: xxxxx (code=exited, status=1/FAILURE)
Sep 04 13:46:24 ip-x-y-z-r systemd[1]: Unit logstash.service entered failed state.
Sep 04 13:46:24 ip-x-y-z-r systemd[1]: logstash.service failed.
Sep 04 13:46:24 ip-x-y-z-r systemd[1]: logstash.service holdoff time over, scheduling restart.
Sep 04 13:46:24 ip-x-y-z-r systemd[1]: Stopped logstash.
Sep 04 13:46:24 ip-x-y-z-r systemd[1]: start request repeated too quickly for logstash.service
Sep 04 13:46:24 ip-x-y-z-r systemd[1]: Failed to start logstash.
Sep 04 13:46:24 ip-x-y-z-r systemd[1]: Unit logstash.service entered failed state.
Sep 04 13:46:24 ip-x-y-z-r systemd[1]: logstash.service failed.
Now, When i visit /var/log/logstash/logstash-plain.log it is not updated.