The command to check last boot’s journal log shows nothing on CentOS 7:
# journalctl -b -1 Failed to look up boot -1: No such boot ID in journal
Is the log stored and where it is?
The reason this happens on CentOS 7 is that CentOS 7 by default does not enable the persistent storage of log messages. You can enable it and configure journald to store the log files into `/var/log/journal` by
# mkdir /var/log/journal # systemd-tmpfiles --create --prefix /var/log/journal # systemctl restart systemd-journald