By default stdout and stderr of a systemd unit are sent to syslog.
以filebeat service 为例:
[Unit] Description=filebeat StartLimitIntervalSec=0 [Service] Type=simple Restart=on-failure RestartSec=1 ExecStart=/data/filebeat/filebeat -e -c /data/filebeat/filebeat.yml StandardOutput=append:/var/log/filebeat/filebeat.log StandardError=append:/var/log/filebeat/filebeat.log [Install] WantedBy=multi-user.target
Now, we can watch the file for our service’s stdout and stderr: