I’ve been doing a lot of Nagios deployments recently, and this error always bites me, on all Ubuntu versions, including Hardy and Intrepid (haven’t quite bit the bullet to try the Jaunty beta yet 🙂 )
Error: Could not stat() command file '/var/lib/nagios3/rw/nagios.cmd'!
The external command file may be missing, Nagios may not be running, and/or Nagios may not be checking external commands.
An error occurred while attempting to commit your command for processing.
This can be quite easily fixed with the following command line fu:
sudo /etc/init.d/nagios3 stop
sudo dpkg-statoverride --update --add nagios www-data 2710 /var/lib/nagios3/rw
sudo dpkg-statoverride --update --add nagios nagios 751 /var/lib/nagios3
sudo /etc/init.d/nagios3 start
Now you should be able to send Nagios remote commands and commands via the web interface to your heart’s content!
For more Nagios advice, I recommend Nagios by O’Reilly. It’s full of best practice advice and covers solving more ‘gotchas’ that you might encounter whilst using it!