Operating System and Software
- Rocky Linux 8
Problem
- On boot, there is no /var/log/dmesg file after install Rocky Linux 8.
- I can get dmesg file via command dmesg, is this new design for Rocky Linux 8, or do I need to modify some configuration to generate it automatically?
How to Fix
Re-enabling the /var/log/dmesg log file
1) Create a /etc/systemd/system/dmesg.service configuration file with the following contents
[Unit]
Description=Create /var/log/dmesg on boot
ConditionPathExists=/var/log/dmesg
[Service]
ExecStart=/usr/bin/dmesg
StandardOutput=file:/var/log/dmesg
[Install]
WantedBy=multi-user.target
2) Create the /var/log/dmesg file and verify SELinux contexts
# touch /var/log/dmesg
# restorecon -v /var/log/dmesg
3) Enable the service to start on boot
# systemctl enable dmesg
Origin of the Problem
By design, the /var/log/dmesg file is not generated during boot. The kernel ring buffer is captured within the systemd-journal as well as /var/log/messages, via the imjournal rsyslog plugin.