I recently installed nagios on a test VM running Ubuntu 10.04 LTS desktop using instructions from: ubuntugeek.com/nagios-networ … buntu.html
I also installed php5 and libapache2-mod-php5 which the instructions did not include. My problem is that I cannot get the nagios daemon to run on startup. Every time I need to start it manually.
While you reboot the machine look for the output for nagios on the screen, it should tell you why it doesn’t start.
If you don’t see anything, make sure that you have added nagios to the default runlevels, otherwise it won’t start.
Furthermore you can increase the log level and verbosity in nagios.cfg then look at nagios.debug and nagios.log and /var/log/messages after you rebooted the machine.