Packer Config for Network Booting a Pi 4

netboot-pi-config.json

{
  "variables": {
    "eth0_ipv4": "",
    "eth0_ipv6": "",
    "eth0_gateway": "",
    "eth0_dns": "",
    "hostname": "",
    "iscsi_initiator_iqn": "",
    "iscsi_target_iqn": "",
    "iscsi_target_ip": "",
    "ntpd_servers": "",
    "root_pub_key": ""
  },
  "builders": [{
    "type": "arm-image",
    "image_type": "raspberrypi",
    "iso_url": "http://downloads.raspberrypi.org/raspios_lite_armhf/images/raspios_lite_armhf-2020-05-28/2020-05-27-raspios-buster-lite-armhf.zip",
    "iso_checksum_type": "sha256",
    "iso_checksum": "f5786604be4b41e292c5b3c711e2efa64b25a5b51869ea8313d58da0b46afc64"
  }],
  "provisioners": [
    {
      "type": "shell",
      "environment_vars": [
        "DEBIAN_FRONTEND=noninteractive",
        "DEBCONF_NONINTERACTIVE_SEEN=true"
      ],
      "inline": [
        "echo 'tzdata tzdata/Areas select US' | debconf-set-selections",
        "echo 'tzdata tzdata/Zones/US select Pacific' | debconf-set-selections",
        "rm /etc/timezone",
        "rm /etc/localtime",
        "dpkg-reconfigure -f noninteractive tzdata"
      ]
    },
    {
      "type": "shell",
      "inline": [
        "apt update",
        "apt full-upgrade -y"
      ]
    },
    {
      "type": "shell",
      "inline": [
        "echo 'Setting up network...'",
        "echo interface eth0 >> /etc/dhcpcd.conf",
        "echo static ip_address={{user `eth0_ipv4`}} >> /etc/dhcpcd.conf",
        "echo static ip6_address={{user `eth0_ipv6`}} >> /etc/dhcpcd.conf",
        "echo static routers={{user `eth0_gateway`}} >> /etc/dhcpcd.conf",
        "echo static domain_name_servers={{user `eth0_dns`}} >> /etc/dhcpcd.conf"
      ]
    },
    {
      "type": "shell",
      "inline": [
        "echo 'Setting up hostname...'",
        "echo {{user `hostname`}} > /etc/hostname",
        "sed -i -r -e 's/(.*)raspberrypi(.*?)$/\\1{{user `hostname`}}\\2/g' /etc/hosts"
      ]
    },
    {
      "type": "shell",
      "inline": [
        "echo 'Setting up NTP...'",
        "sed -i -r -e 's/#?NTP.*?$/NTP={{user `ntpd_servers`}}/g' /etc/systemd/timesyncd.conf"
      ]
    },
    {
      "type": "shell",
      "inline": [
        "echo 'Setting up sshd...'",
        "touch /boot/ssh",
        "sed -i -r -e 's/#?.*?PermitRootLogin.*?$/PermitRootLogin without-password/g' /etc/ssh/sshd_config",
        "sed -i -r -e 's/#?.*?PasswordAuthentication.*?$/PasswordAuthentication no/g' /etc/ssh/sshd_config",
        "mkdir -p /root/.ssh/",
        "chmod 700 /root/.ssh",
        "echo {{user `root_pub_key`}} >> /root/.ssh/authorized_keys",
        "chmod 644 /root/.ssh/authorized_keys"
      ]
    },
    {
      "type": "shell",
      "inline": [
        "echo 'Disabling wifi...'",
        "echo 'dtoverlay=disable-wifi' >> /boot/config.txt"
      ]
    },
    {
      "type": "shell",
      "inline": [
        "echo 'Disabling bluetooth...'",
        "echo 'dtoverlay=disable-bt' >> /boot/config.txt"
      ]
    },
    {
      "type": "shell",
      "inline": [
        "echo 'Installing additional packages...'",
        "apt install -y initramfs-tools open-iscsi vim"
      ]
    },
    {
      "type": "shell",
      "inline": [
        "echo 'Setting up /etc/iscsi/iscsi.initramfs...'",
        "echo ISCSI_INITIATOR={{user `iscsi_initiator_iqn`}} > /etc/iscsi/iscsi.initramfs",
        "echo ISCSI_TARGET={{user `iscsi_target_iqn`}} >> /etc/iscsi/iscsi.initramfs",
        "echo ISCSI_TARGET_IP={{user `iscsi_target_ip`}} >> /etc/iscsi/iscsi.initramfs",
        "echo 'Setting up /etc/iscsi/initiatorname.iscsi...'",
        "echo InitiatorName={{user `iscsi_initiator_iqn`}} > /etc/iscsi/initiatorname.iscsi"
      ]
    }
  ]
}