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Troubleshooting Log Files

The only real unique entity for logging on Cumulus RMP compared to any other Linux distribution is switchd.log, which logs the HAL (hardware abstraction layer) from hardware like the Broadcom ASIC.

This guide on NixCraft is amazing for understanding how /var/log works. The green highlighted rows below are the most important logs and usually looked at first when debugging.




Information from the update-alternatives are logged into this log file.


Information the apt utility can send logs here; for example, from apt-get install and apt-get remove.


Contains log information stored by the Linux audit daemon, auditd.


Authentication logs.


Contains information that is logged when the system boots.


This file contains information about failed login attempts. Use the last command to view the btmp file. For example:

last -f /var/log/btmp | more    


Contains information logged by the various background daemons that run on the system.


Contains kernel ring buffer information. When the system boots up, it prints number of messages on the screen that display information about the hardware devices that the kernel detects during boot process. These messages are available in the kernel ring buffer and whenever a new message arrives, the old message gets overwritten. You can also view the content of this file using the dmesg command.


Contains information that is logged when a package is installed or removed using the dpkg command.


Contains failed user login attempts. Use the faillog command to display the contents of this file.


The fsck utility is used to check and optionally repair one or more Linux filesystems.


Mail server logs.


General messages and system related information.


monit is a utility for managing and monitoring processes, files, directories and filesystems on a Unix system.


The news command keeps you informed of news concerning the system.


Logs for network configuration protocol.


Kernel logs.


The HAL log for Cumulus RMP.


The main system log, which logs everything except auth-related messages.


Login records file.


apt command log file.