At default the external commands for nagios are deactivated. To activate them, we have to adapt the nagios configuration.
I write just a short command summary. The whole documentation can be found at
First of all we need to activate external commands for nagios. That can be done
check_external_commands to 1 in nagios.cfg:
vi /etc/nagios3/nagios.cfg ... check_external_commands=1 ...
After that we need to change directory permissions and make the changes permament (all commands need to be executed as root):
service nagios3 stop dpkg-statoverride --update --add nagios www-data 2710 /var/lib/nagios3/rw dpkg-statoverride --update --add nagios nagios 751 /var/lib/nagios3 service nagios3 start
The specific part in README.Debian:
Nagios 3 is not configured to look for external commands in the default configuration as a security feature. To enable external commands, you need to allow the web server write access to the nagios command pipe. the simplest way of doing this is to set check_external_commands=1 in your nagios configuration, and then change the permissions in a way which will be maintained across package upgrades (otherwise dpkg will overwrite your permission changes). The following is the recommended approach: - activate external command checks in the nagios configuration. this can be done by setting check_external_commands=1 in the file /etc/nagios3/nagios.cfg. - perform the following commands to change directory permissions and to make the changes permanent: /etc/init.d/nagios3 stop dpkg-statoverride --update --add nagios www-data 2710 /var/lib/nagios3/rw dpkg-statoverride --update --add nagios nagios 751 /var/lib/nagios3 /etc/init.d/nagios3 start