Logging is done using journalctl .

See for example https://www.digitalocean.com/community/tutorials/how-to-use-journalctl-to-view-and-manipulate-systemd-logs

See http://pm2.keymetrics.io/docs/usage/log-management/

  pm2 logs

• pm2 log is found in /root/.pm2/logs/pm2.log
• webic stdout log in /var/local/logs/webic-out.log
• webic error log in /var/local/logs/webic-err.log