notes

Logging

systemd-journald

1. By default logs are stored in memory.
2. stdout and stderr from units by default goes to systemd-journald
3. View logs
   • journalctl -xe - show errors
   • journalctl --list-boots - list all boots (the same as last)
   • journalctl -b -2 - logs for last 2 boots
   • journalctl --since "2017-05-05 00:01" --until "2017-05-06 01:40" - logs for date range
   • journalctl --since "10 hours ago" - logs for last 10 hours
   • journalctl -u unit-name.service -f - logs for specific units
   • journalctl _UID=1001 - logs for user with id 1001
   • journalctl -n 3 -p crit - last 3 critical logs
4. Operate with logs
   • journalctl --flush - put all log data from memory into disk
   • journalctl --rotate
   • journalctl --sync
   • journalctl --vacuum-size=1G - cleanup old logs to that log size become no more than 1G
   • journalctl --vacuum-time=1years - cleanup logs older than 1 year
   • journalctl --disk-usage - show logs disk usage