Adding all hosts in subnet to icinga monitoring without specifying hostname/IP

Question

I have a provisioning system setting up new hosts to be in the domain test.domain.local, i.e. client44.test.domain.local, and I have an Icinga server which I would like to automatically monitor all these hosts using regex, like *.test.domain.local.

All the clients will get nagios-nrpe-server (version. 2.13-3) package, which is also configured to allow the icinga-server to fetch data from them, and this has been verified to be working.

We're just for now going to monitor services/things we know all the nodes will have, for example SSH, response to ping etc.

I have looked at this link but I don't quite the relationship between hosts, hostgroups and service classes?

Both the Icinga server and all the clients run Debian.

score 2 · Accepted Answer · answered May 14 '14 at 11:47

I've been working with fredmu on this problem, and came up with a working solution inspired by Tim Brigham's answer.

Using the default generic-host definition this could be solved using script that automatically generates host configuration files based off a template. Optionally it could be done as a cronjob to generate these file on a routinely basis.

generate_host_cfg.sh

#!/usr/bin/env bash

icinga_root="/etc/icinga/objects"
subnet="10.0.0.*"
template="template_icinga.cfg"
alias_file="alias.txt"

# navigate to the Icinga configuration directory
cd $icinga_root

# create first server alias if doesn't exist
if [ ! -e $alias_file ]; then
    echo "1" > $alias_file
fi

# iterate through subnet, store "hostname:ip" in associative array
declare -A address

for host in $(nmap -sP $subnet | awk -F '[ ()]' '/for [a-z]+/ {print $5 ":" $7}'); do
    address[$(echo $host | cut -d: -f1)]=$(echo $host | cut -d: -f2)
done

# iterate through hosts, create files if not exist based off template
for host in ${!address[@]}; do
    host_file=${host}_icinga.cfg

    if [ ! -e $host_file ]; then
        # fetch new server alias
        alias=$(cat $alias_file)

        # create the next server alias
        expr $alias + 1 > $alias_file

        # create hostname_icinga.cfg if doesn't exist, based off template
        cp $template $host_file

        # replace contents of new template; hostname, alias and ip
        sed -i -r \
            -e "s/tmp-hostname/$host/" \
            -e "s/tmp-alias/Server$alias/" \
            -e "s/tmp-address/${address[$host]}/" $host_file
    fi

done

template_icinga.cfg

define host{
        use                     generic-host
        host_name               tmp-hostname
        alias                   tmp-alias
        address                 tmp-address
        }

Resulting in files like these:

define host{
        use                     generic-host
        host_name               monitor.company.local
        alias                   Server1
        address                 10.0.0.1
        }

works nicley, thanks a lot. You do need working DNS and nmap installed. — fredmu, May 14 '14 at 12:31

score 1 · Answer 2 · answered May 12 '14 at 03:22

There are a lot of ways to tackle this.

I have previously assembled bash scripts which would run as a single icinga check. The script would then check all the hosts in the subdomain and return a state based on if or how many failures are found.

More recently I've become a fan of custom facts in puppet. Combined with a well writeb template you can easily add your checks across a large number of nodes using a for loop.

Adding all hosts in subnet to icinga monitoring without specifying hostname/IP

2 Answers2