Universal U(EFI) bootstrap from inside

bootstrap.sh

#!/bin/bash

# USAGE: ./bootstrap.sh <swap_partition>
# DESCRIPTION: Overwrites swap partition with netboot.xyz image and adds efibootmgr entry for next boot
# LICENSE: LGPL3.0-only

# for OCI, currently you'll have to connect to your console via VNC after reboot
# https://docs.oracle.com/en-us/iaas/Content/Compute/References/serialconsole.htm#Connecti
# and proceed through the "graphical" installer

# adapted from alpine-bootstrap v1.0 by sdomi http://sdomi.pl/weblog/12-bootstrapping-alpine-on-oraclecloud/

set -eo pipefail

# set variables
swap=$1
disk=""
part=""

if [[ "$(whoami)" != "root" ]]; then
  echo "This script needs to be run as root."
  exit 1
fi

# functions
function findcmd {
  if ! command -V "$1" > /dev/null 2>&1; then
    echo "$1 not found. Please install it."
    exit 1
  fi
}

function findswap {
  # check if provided swap is mounted
  if [[ -n "$swap" ]] && swapon --show=name --noheadings | grep -q "$swap"; then
    echo "Swap found from argument: $swap"
  else
    # find all swaps
    # shellcheck disable=SC2162
    read -a swapdefns <<< "$(swapon --show=name,type --noheadings)"
    # check if swap is a partition
    if [[ "${swapdefns[1]}" == "partition" ]]; then
      swap="${swapdefns[0]}"
    elif [[ "${swapdefns[1]}" == "file" ]]; then
      echo "Swap is a file. Please specify a swap partition."
      exit 1
    else
      echo "No swap partition found?"
      echo "We'll need a 3MB+ partition. Specify which with $0 <dev_path>"
      exit 1
    fi
    # parse partition and disk
  fi
  disk=$(grep -Poh "^([\w\/]+)(?:[0-9])$" <<< "$swap")
  part=$(grep -Poh "[0-9]$" <<< "$swap")
}

# check for commands
findcmd curl &&
  findcmd dd &&
  findcmd efibootmgr &&
  findcmd grep &&
  findcmd swapon &&
  findcmd swapoff

# find swap
findswap
echo "Annihilating swap ..."
swapoff "$swap"

echo "Downloading netboot.xyz to swap partition ..."
curl -sL https://boot.netboot.xyz/ipxe/netboot.xyz.img | dd of="$swap"
echo "Adding efibootmgr entry ..."
efibootmgr -cq -d "$disk" -p "$part" -L netboot.xyz -l "\EFI\BOOT\BOOTX64.EFI"
echo "Setting netboot.xyz as first boot option ..."
order=$(efibootmgr | grep netboot.xyz | grep -Poh "[0-9]{4}")
efibootmgr -qo "$order"
echo "Reboot your machine to enter netboot.xyz"

ol7.sh

#!/bin/bash

# USAGE: ./ol7.sh
# DESCRIPTION: OL7 to netboot.xyz script
# LICENSE: LGPL3.0-only

# for OCI, currently you'll have to connect to your console via VNC after reboot
# https://docs.oracle.com/en-us/iaas/Content/Compute/References/serialconsole.htm#Connecti
# and proceed through the "graphical" installer

# adapted from alpine-bootstrap v1.0 by sdomi http://sdomi.pl/weblog/12-bootstrapping-alpine-on-oraclecloud/

set -eo pipefail

if [[ "$(whoami)" != "root" ]]; then
  echo "This script needs to be run as root."
  exit 1
fi

# check for OL7.9
if ! grep -q "Oracle Linux Server 7.9" /etc/oracle-release; then
  echo "This script is for Oracle Linux 7.9 only. Later versions use a swapfile instead of swap partition."
  exit 1
fi

# we know swap is on /dev/sda2
swapoff -a

# download netboot.xyz image
curl -sL https://boot.netboot.xyz/ipxe/netboot.xyz.img | dd of="/dev/sda2"
efibootmgr -cq -d /dev/sda -p 2 -L netboot.xyz -l "\EFI\BOOT\BOOTX64.EFI"
order=$(efibootmgr | grep netboot.xyz | grep -Poh "[0-9]{4}")
efibootmgr -qo "$order"
echo "Reboot your machine to enter netboot.xyz"