Debian/Ubuntu host initialization script

firstrun

#!/bin/bash
set -e

###
# Script to set root password and networking config on first boot. 
# 
# Make your modifications and turn this on by running:
# /etc/init.d/firstrun enable
###


##
# Configure this stuff with your own defaults, these get used in prompts
##

DEF_DOM="oddbox.org"
DEF_IP="10.42.0."
DEF_NM="255.255.0.0"
DEF_GW="10.42.0.1"
DEF_DNS1="198.237.137.20"
DEF_DNS2="198.237.137.21"
DEF_ADMIN="root@$DEF_DOM"
DEF_RELAY="mail.$DEF_DOM"



if [ "$1" == "enable" ]; then
    update-rc.d firstrun start 38 S .
    echo "Enabled firstrun script."
fi

if [ "$1" != "start" ] ; then
    exit
fi

sleep 3 ; clear

echo
echo "Doing initial local config of passwords and networking."
echo "To re-use, read and edit /etc/init.d/firstrun, then run"
echo "/etc/init.d/firstrun enable"
echo


# only prompt in interactive mode
if ! grep -q "noninteractive" /proc/cmdline ; then
    stty sane

    echo "Please specify a root password:"
    while ! passwd ; do : ; done

    if [ -f /usr/bin/vncpasswd ]; then
        echo "Please specify a VNC password:"
        while ! vncpasswd /etc/vncpass ; do : ; done
    fi

    # hostname:
    read -p "Hostname (w/o domain): " hn
    echo "$hn" >/etc/hostname
    hostname $hn

    dpkg -s nullmailer &>/dev/null
    if [ "$?" == "0" ]; then
        read -ei "$DEF_ADMIN" -p "Admin Email Address: " adminaddr
        read -ei "$DEF_RELAY" -p "Mail Server: " relayhost
    fi

    read -e -p "Press enter for DHCP or N for static IP configuration [Y/n] " usedhcp
   
    case "$usedhcp" in
        [Nn])
            read -ei "$DEF_DOM"  -p "Domain name: " dn
            read -ei "$DEF_IP"   -p "Primary IP address: " ipaddr
            read -ei "$DEF_NM"   -p "Subnet Mask: " nm
            read -ei "$DEF_GW"   -p "Gateway: " gw
            read -ei "$DEF_DNS1" -p "First DNS server: " dns1
            read -ei "$DEF_DNS2" -p "Second DNS server: " dns2

            echo "Adding /etc/hosts entry for $ipaddr $hn.$dn"
            echo "$ipaddr  $hn.$dn  $hn" >> /etc/hosts

            echo "Configuring /etc/resolv.conf with DNS servers $dns1 and $dns2 and search of $dn"
            cat /dev/null > /etc/resolv.conf
            echo "search $dn" >> /etc/resolv.conf
            echo "nameserver $dns1" >> /etc/resolv.conf
            echo "nameserver $dns2" >> /etc/resolv.conf

            echo "Reconfiguring interface eth0 via ifupdown..."
            
            of="/etc/network/interfaces"
            cat /dev/null > $of
            echo "auto lo" >> $of
            echo "iface lo inet loopback" >> $of
            echo "" >> $of
            echo "auto eth0" >> $of
            echo "iface eth0 inet static" >> $of
            echo "        address $ipaddr" >> $of
            echo "        netmask $nm" >> $of
            echo "        gateway $gw" >> $of
        ;;
        [Yy]*)
            echo "Setting eth0 as DHCP in /etc/network/interfaces..."
           
            rm -f /var/lib/dhcp3/*leases
            of="/etc/network/interfaces"
            cat /dev/null > $of
            echo "auto lo" >> $of
            echo "iface lo inet loopback" >> $of
            echo "" >> $of
            echo "auto eth0" >> $of
            echo "iface eth0 inet dhcp" >> $of
        ;;    
    esac
fi

hn=`hostname`
dn=$DEF_DOM

echo "Re-generating unique host keys for your SSH server..."
find /etc/ssh -name "ssh_host_*_key*" -exec rm -f {} \;
DEBIAN_FRONTEND=noninteractive DEBIAN_PRIORITY=critical dpkg-reconfigure openssh-server

dpkg -s puppet &>/dev/null && (
    echo "Re-generating unique keys for puppet configuration management..."
    find /var/lib/puppet/ssl -type f -exec rm {} \;
    DEBIAN_FRONTEND=noninteractive DEBIAN_PRIORITY=critical dpkg-reconfigure puppet
    echo "Puppet setup complete. Contact puppetmaster admin to approve keys."
)

dpkg -s postfix &>/dev/null && (
    echo "Reconfiguring postfix mailer"
    rm -f /etc/mailname /etc/postfix/main.cf
    echo "postfix postfix/mailname string $hn.$dn" | debconf-set-selections
    DEBIAN_FRONTEND=noninteractive DEBIAN_PRIORITY=critical dpkg-reconfigure postfix
)

dpkg -s nullmailer &>/dev/null && (
    echo "Reconfiguring nullmailer..."
    rm -f /etc/mailname /etc/nullmailer/*
    echo "nullmailer shared/mailname string $hn.$dn" | debconf-set-selections
    echo "nullmailer nullmailer/adminaddr string $adminaddr" | debconf-set-selections
    echo "nullmailer nullmailer/relayhost string $relayhost" | debconf-set-selections
    DEBIAN_FRONTEND=noninteractive DEBIAN_PRIORITY=critical dpkg-reconfigure nullmailer
)

update-rc.d -f firstrun remove &>/dev/null
echo "done with first-run config."

This is my version of a script first written by @magurski