I use the Nagios plug-in check_log to check my log files for suspecious entires.
However, the module avails with the error message that the log files are not readable.
-rw-r----- 1 root adm 36490 Dec 14 15:31 /var/log/messages
It is just readable for root and adm but not for the user “nagios” who, as I assume, is
executing the Nagios plug-ins. So, how can I solve the permission problem?
Another problem I have since I installed Nagios are strange entries in my /var/log/messages:
*nagios: Error: Could not connect to MySQL database ‘’ on host ‘’ using username ‘’ and password ‘XXXXXX’. Retention data will not be processed or saved!
nagios: Error: Could not re-connect to database server on host ‘’ for status data. I’ll keep trying every 60 seconds…
Where do they come from and how can I solve them?