Linux – nagios nrpe plugin: permission issue

The simplest way is to change the ownership to your userid. This should not be user id the webserver is accessing the files you are using. Use the chown command recursively. Try a command like:

sudo chown -R $LOGNAME /var/www

This will recursively change the /var/www directory tree to your userid. LOGNAME is normally set to your userid. This can be verified with the command echo $LOGNAME.

Limit write access by the web server to as few directories and files as possible.

OK, I've been trawling though the Nagios3 documentation and have answered the port configuration part of my question...

The answer lies in the Object Inheritance model that exists within the Nagios configuration files. Essentially I created a custom variable in each host definition that specifies the unique ssh port on that machine:

define host {
    use              generic-host
    host_name        serverB
    address          10.0.1.3
    _sshport         67382
}

The hosts are grouped together inside the hostgroups_nagios2.cfg file:

# A list of your ssh-accessible servers
define hostgroup {
    hostgroup_name  ssh-servers
    alias           SSH servers
    members         localhost,serverB,serverC
}

This group is referenced inside the services_nagios2.cfg by the block that checks SSH:

# check that ssh services are running
define service {
    hostgroup_name                  ssh-servers
    service_description             SSH
    check_command                   check_ssh_port!$_HOSTSSHPORT
    use                             generic-service
    notification_interval           0 ; set > 0 if you want to be renotified
}

At the end of the check_ssh_port command you can see that I added the sshport variable $_HOSTSSHPORT that is inherited from each host inside the ssh-servers hostgroup as the checks are run.

Now, when adding new servers, I only have to modify my hosts_nagios2.cfg file with the details of the new host.

To enable backward compatibility, I also modified my generic-host_nagios2.cfg file adding the line _sshport 22 so that if for some reason I need to monitor some system running SSH on the default port, the port config will already be inherited from the generic host template.

I hope this helps others who find themselves in the same predicament. I am still trying to understand why the remote checks aren't using the custom config files on the remote servers.