Script for generating Icinga host definitions

generate_host_cfg.sh

#!/usr/bin/env bash

# generates a valid [host] configuration file for Icinga
# based off a template, for all the hosts in the subnet
icinga_root="/etc/icinga/objects"
subnet="10.0.0.1.*"
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
# http://www.tldp.org/LDP/abs/html/bashver4.html
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
        }