pxeboot/create_pxeinitrd.sh

#!/bin/bash
set -Eeuxo pipefail

DEBNAME=${DEBNAME:=wit-pxeboot}

SIZE=10000
HOSTNAME=localhost
RELEASE=unstable

TMP_DIR=$(mktemp -d)
MNT_DIR=$TMP_DIR/newroot
RESULT_DIR=${RESULT_DIR:=/tmp/result}


# Configs overwritable via environment variables
FLAVOUR=${FLAVOUR:=debian}					# Either 'debian' or 'ubuntu'
INCLUDES=${INCLUDES:="openssh-server,init,curl,vim,locales-all,less,ceph-common,dmidecode,iputils-ping,fping,tcpdump,rsync,ethtool,lldpd,iproute2,net-tools,sudo,gnupg,tcpdump,mtr-tiny,ifupdown,ipmitool,iptables,telnet,netcat,bridge-utils,vlan,ifstat,ncurses-term,wget,dhcpcd5"}
MIRROR=${MIRROR:="https://mirrors.wit.com/debian"}
ARCH=${ARCH:=amd64}


clean_debian() {
	[ "$TMP_DIR" != "" ] && rm -r $TMP_DIR
}

fail() {
	clean_debian
	echo ""
	echo "FAILED: $1"
	exit 1
}

cancel() {
	fail "CTRL-C detected"
}

trap cancel INT

mkdir $MNT_DIR


if [ $FLAVOUR == "debian" ]; then
    BOOT_PKG="linux-image-$ARCH"
elif [ $FLAVOUR == "ubuntu" ]; then
    BOOT_PKG="linux-image-generic"
fi


###################
## build root fs ##
###################


echo "Installing Debian $RELEASE..."
debootstrap --variant=minbase --include=$INCLUDES $RELEASE $MNT_DIR $MIRROR || fail "cannot install $RELEASE"

echo $HOSTNAME > $MNT_DIR/etc/hostname

cat <<EOF > $MNT_DIR/etc/hosts
127.0.0.1       localhost
# The following lines are desirable for IPv6 capable hosts
::1     localhost ip6-localhost ip6-loopback
ff02::1 ip6-allnodes
ff02::2 ip6-allrouters
EOF


rm -f $MNT_DIR/etc/apt/sources.list
echo 'deb https://mirrors.wit.com/debian sid main contrib non-free' > $MNT_DIR/etc/apt/sources.list
echo 'deb https://mirrors.wit.com/debcore sid main' >> $MNT_DIR/etc/apt/sources.list
curl https://mirrors.wit.com/debcore/public.key | LANG=C DEBIAN_FRONTEND=noninteractive chroot $MNT_DIR apt-key add -
LANG=C DEBIAN_FRONTEND=noninteractive chroot $MNT_DIR apt-get update
LANG=C DEBIAN_FRONTEND=noninteractive chroot $MNT_DIR apt-get install -y $BOOT_PKG || fail "cannot install $BOOT_PKG"


chroot $MNT_DIR apt-get clean || fail "unable to clean apt cache"
cat /dev/null > $MNT_DIR/etc/machine-id

sed -i '/PasswordAuthentication/d' $MNT_DIR/etc/ssh/sshd_config
echo "PasswordAuthentication no" >>$MNT_DIR/etc/ssh/sshd_config

mkdir -p $MNT_DIR/root/.ssh
echo ssh-rsa AAAAB3NzaC1yc2EAAAADAQABAAABAQDd7rLlS1NmTpBr5KP5ryuA/euGD8I6uc2RCg4sCIlvH0FhEPb123QuMVImHi23ftVP61cKZXm8MlTtAoLHduYtGMHCkJWAAkiIpPetAP2KPIpuadtgIS8xuD/TCYjl0xNXLh0M1C7i7HOnTd8yr+3QNjUppyDdKjLvMQbPWZZTU5rt7CYoGlrxHjieCkq9jj8kRjRARUaAJ4DHEgMFUDIcq3JYluzzkgPK/JFwoq/IokVQCr5qfQRwr3SCkD4sIuGTj+J67uzabIr/xDBqlrMW3T+7YfY12ciHpijob+l7xESkJ+6Gxh56z8llBkGiVyh3UqnmW4MvfuAA/D3Dzhwr afrank@adams-mbp.lan > $MNT_DIR/root/.ssh/authorized_keys

cat <<EOF > $MNT_DIR/etc/systemd/system/start-me-up.service
[Unit]
Description=WIT System Startup
Wants=network-online.target
After=network-online.target

[Service]
Type=oneshot
ExecStart=/usr/local/bin/start_me_up.sh
RemainAfterExit=true
ExecStop=/usr/local/bin/shut_me_down.sh
StandardOutput=journal

[Install]
WantedBy=multi-user.target
EOF


cat <<EOF > $MNT_DIR/usr/local/bin/start_me_up.sh
#!/bin/bash
eval "kernel_args=( \$(cat /proc/cmdline) )"
for i in "\${kernel_args[@]}"
 do
   if [ \${i:0:4} = exec ]
     then
       export -- "\$i"
   fi
done

echo \$execstartup
eval \$execstartup
EOF


cat <<EOF > $MNT_DIR/usr/local/bin/shut_me_down.sh
#!/bin/bash
eval "kernel_args=( \$(cat /proc/cmdline) )"
for i in "\${kernel_args[@]}"
 do
   if [ \${i:0:4} = exec ]
     then
       export -- "\$i"
   fi
done

echo \$execshutdown
eval \$execshutdown
EOF


cat <<EOF >$MNT_DIR/root/install.sh
#!/bin/bash
set -eo pipefail
export INSTALLEXTRA="\$@"
curl http://roberto.wit.com:8081/create_local_install.sh | bash
EOF


cat <<EOF >$MNT_DIR/etc/dhcpcd.conf
hostname
duid
slaac hwaddr
noipv4ll
option domain_name_servers, domain_name, domain_search, host_name
option classless_static_routes, ntp_servers, interface_mtu
require dhcp_server_identifier
EOF


chmod +x $MNT_DIR/root/install.sh
chmod +x $MNT_DIR/usr/local/bin/start_me_up.sh
chmod +x $MNT_DIR/usr/local/bin/shut_me_down.sh

chroot $MNT_DIR systemctl enable start-me-up || fail "failed to enable start-me-up"



#echo "Enter root password:"
#while ! chroot $MNT_DIR passwd root
#do
#	echo "Try again"
#done



###############
## deb build ##
###############


mkdir -p $RESULT_DIR/debian
echo -e "$DEBNAME (1.0.$(date +%Y.%m.%d.%H.%M)) unstable; urgency=low\n\n$(git log --format="  * %s")\n\n -- wit <netops@wit.com>  $(date -R)" >$RESULT_DIR/debian/changelog

echo "11" >$RESULT_DIR/debian/compat

cat <<EOF >$RESULT_DIR/debian/$DEBNAME.install
./vmlinuz /srv/tftp/wit-pxeboot/
./initramfs.gz /srv/tftp/wit-pxeboot/
EOF


cat <<EOF >$RESULT_DIR/debian/control
Source: $DEBNAME
Section: unknown
Priority: optional
Maintainer: wit <netops@wit.com>
Build-Depends: debhelper (>= 11)
Standards-Version: 4.1.3
Homepage: http://www.wit.com

Package: $DEBNAME
Architecture: all
Depends: \${misc:Depends}, tftpd-hpa
Description: kernel and initrd to pxeboot debcore
 kernel and initrd to boot a pxe image easily
 it also includes a rootfs to quickly kickstart
 a local install
EOF


cat <<"EOF" >$RESULT_DIR/debian/rules
#!/usr/bin/make -f
# See debhelper(7) (uncomment to enable)
# output every command that modifies files on the build system.
#export DH_VERBOSE = 1


# see FEATURE AREAS in dpkg-buildflags(1)
#export DEB_BUILD_MAINT_OPTIONS = hardening=+all

# see ENVIRONMENT in dpkg-buildflags(1)
# package maintainers to append CFLAGS
#export DEB_CFLAGS_MAINT_APPEND  = -Wall -pedantic
# package maintainers to append LDFLAGS
#export DEB_LDFLAGS_MAINT_APPEND = -Wl,--as-needed


%:
	dh $@


# dh_make generated override targets
# This is example for Cmake (See https://bugs.debian.org/641051 )
#override_dh_auto_configure:
#	dh_auto_configure -- #	-DCMAKE_LIBRARY_PATH=$(DEB_HOST_MULTIARCH)

EOF






##################
## build initrd ##
##################


mkdir -p $TMP_DIR/initramfs/bin
wget -O $TMP_DIR/initramfs/bin/busybox https://www.busybox.net/downloads/binaries/1.26.1-defconfig-multiarch/busybox-x86_64
chmod +x $TMP_DIR/initramfs/bin/busybox

cat > $TMP_DIR/initramfs/init << EOF
#!/bin/busybox sh

# Dump to sh if something fails
error() {
  echo "Jumping into the shell..."
  setsid cttyhack sh
}

# Populate /bin with binaries from busybox
/bin/busybox --install /bin

mkdir -p /proc
mount -t proc proc /proc

mkdir -p /sys
mount -t sysfs sysfs /sys

mkdir -p /sys/dev
mkdir -p /var/run
mkdir -p /dev

mkdir -p /dev/pts
mount -t devpts devpts /dev/pts

# Populate /dev
echo /bin/mdev > /proc/sys/kernel/hotplug
mdev -s

mkdir -p /newroot
mount -t tmpfs -o size=${SIZE}m tmpfs /newroot || error

echo "Extracting rootfs... "
xz -d -c -f rootfs.tar.xz | tar -x -f - -C /newroot || error

mount --move /sys /newroot/sys
mount --move /proc /newroot/proc
mount --move /dev /newroot/dev

exec switch_root /newroot /sbin/init || error
EOF

chmod +x $TMP_DIR/initramfs/init

cd $TMP_DIR/newroot
tar cJf $TMP_DIR/initramfs/rootfs.tar.xz .

cd $TMP_DIR/initramfs
mkdir -p $RESULT_DIR
find . -print0 | cpio --null -ov --format=newc | gzip -9 > $RESULT_DIR/initramfs.gz

cp $TMP_DIR/newroot/boot/vmlinuz-* $RESULT_DIR/vmlinuz

ls -la $RESULT_DIR/



#############
## cleanup ##
#############


clean_debian
exit 0