build_qemu_debian_image.sh

#!/bin/bash -e

DISTRO=buster
if test $# -eq 1; then
    DISTRO=$1
fi

TEMP="$(mktemp -d build.XXXXX)"
cp preseed.cfg $TEMP
pushd $TEMP

AUTHORIZED_KEYS="$(ssh-add -L)"
if [ -n "$AUTHORIZED_KEYS" ]
then
	echo "Pre-populating authorized_keys for image"
	echo "$AUTHORIZED_KEYS" > authorized_keys
fi

ROOT_PASSWORD="$(openssl rand -base64 18)"
echo "vvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvv"
echo "==> Randomised root password is: $ROOT_PASSWORD <=="
echo $ROOT_PASSWORD > ../root-pass.txt
echo "^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^"
CRYPTED_PASSWORD="$(openssl passwd -1 -salt xyz $ROOT_PASSWORD)"

echo "Running simple webserver on port 4321 for host files..."
PYTHON_PID=$(sh -c 'echo $$ ; exec >/dev/null 2>&1 ; exec python3 -m http.server 4321' &)

echo "Running netcat to capture syslogs..."
NC_PID=$(sh -c 'echo $$ ; exec > ../installer.log 2>&1 ; exec nc -ul 10514' &)

echo "Downloading Debian $DISTRO x86_64 netboot installer..."
if ! test -f ../netboot.tar.gz; then
    curl --location --output ../netboot.tar.gz https://deb.debian.org/debian/dists/$DISTRO/main/installer-amd64/current/images/netboot/netboot.tar.gz
fi
mkdir -p tftpserver
pushd tftpserver
tar xzvf ../../netboot.tar.gz

echo "Customising network boot parameters..."
cat > debian-installer/amd64/pxelinux.cfg/default <<EOF
serial 0
prompt 0
default autoinst
label autoinst
kernel debian-installer/amd64/linux
append initrd=debian-installer/amd64/initrd.gz auto=true priority=critical passwd/root-password-crypted=$CRYPTED_PASSWORD DEBIAN_FRONTEND=text url=http://10.0.2.2:4321/preseed.cfg log_host=10.0.2.2 log_port=10514 --- console=ttyS0
EOF
popd

echo "Creating disk image for Debian $DISTRO x86_64..."
qemu-img create -f qcow2 ../debian-$DISTRO.qcow 10G

VMNAME="$DISTRO"vm
echo "Running Debian Installer..."
qemu-system-x86_64 \
	-hda ../debian-$DISTRO.qcow \
	-netdev user,id=net0,net=10.0.2.0/24,hostname=$VMNAME,domainname=localdomain,tftp=tftpserver,bootfile=/pxelinux.0 \
	-device e1000,netdev=net0,mac=52:54:98:76:54:32 \
	-boot once=n \
	-m 2048 \
	-nographic

echo "Removing temporary directory $TEMP ..."
popd
rm -rf $TEMP

echo "Cleaning up processes..."
kill $PYTHON_PID
kill $NC_PID