Inode Ltd

Organising Nagios config files

Nagios is great, but I still get annoyed with the standard configuration setup. Hosts, Hostgroups, Services … whenever you add a new host, there are a lot of places to touch to get it configured properly.

Most customers think of their network in terms of “hosts” — they add a physical host, they run services on that host, they want to monitor that host. So how can we reduce the amount of config work to be done?

I’ve started to play with a scheme I’m calling ‘capabilities’. A capability is a combination of a hostgroup and a service definition, both with the same name. Here’s the “ssh” capability :-

### SSH {{{
define hostgroup{
    hostgroup_name      ssh
    alias               Hosts with ssh on TCP:22
}
define service{
    hostgroup_name      ssh
    service_description ssh
    check_command       check_ssh
    use                 service.template
}
# }}} ssh

All I have to do in order to have checks against this capability is to add the host to the hostgroup ’ssh’, and I can do this directly from the host object itself …

define host{
    host_name       benjamin
    alias           Mail Server
    address         10.11.12.13
    use             host.template
    hostgroups      ssh,smtp
}

No messing around with specifying this host anywhere else, all the references it needs in order to exist are in one file, and so are the complete set of references to the service checks that will be performed.

Now admittedly, this does add extra hostgroups to the CGI interface, and if you are using that on a regular basis you may not appreciate the extra clutter. However, for the sorts of thing I’m doing, it’s more important to be able to quickly and accurately describe a host & associated checks.

Tags: nagios