systemd-journald#
Writes system logging to a binary file. By default only logs since the last boot.
journalctl#
Most useful journalctl options:
| Option | Use |
|---|---|
| -f | Follow the end of journal in real-time, like tail -f |
| -b | Show the boot logs |
| -x | Explain each log entry in detail |
| -u | Filter logs for a specific systemd unit |
| -p | Filter logs for messages with a specific priority |
| -e | Go to end of logs |
Conf#
Systemd-journald conf: /etc/systemd/journald.conf
Configure persistent journal logging#
From man systemd-journald:
The journal service stores log data either persistently below /var/log/journal or in a volatile way below /run/log/journal/ (in the latter case it is lost at reboot). By default, log data is stored persistently if /var/log/journal/ exists during boot
On systems where /var/log/journal/ does not exist yet but where persistent logging is desired (and the default journald.conf is used), it is sufficient to create the directory, and ensure it has the correct access modes and ownership:
mkdir -p /var/log/journal
systemd-tmpfiles --create --prefix /var/log/journal
Then switch to persistent logging with:
journalctl --flush
# or
systemctl restart systemd-journald