Nagios web-interface can fail to connect to process or to display any content at all. There can be different source of the problem, but the key to solving it:
- Checking permissions on the cgi-bin, fcgi-bin folders and scripts inside /nagios path.
- Checking Suexec log if you use it (`/var/log/apache2/suexec.log` for example).
- Checking access mode on statusjson.cgi and status.cgi
In case it doesn’t help, and nagios simply refuses to start, showing only:
Running configuration check...
or
Starting nagios:.
You have to manually run configuration check with the -v flag:
/usr/local/nagios/bin/nagios -v /usr/local/nagios/etc/nagios.cfg
If the check is correct, but nags refuses to run, providing no info in {path}/var/nagios.log and not creating {path}/var/nagios.lock, then the problem might be in the device space.