example packer

config--ubuntu-2004.pkr.hcl

vm_name = "ubuntu-server-24.04-template"
vm_id = 9104

config--vm.pkr.hcl

proxmox_node = "s2"

vm_scsi_controller = "virtio-scsi-pci"
vm_disk_io_thread = false
vm_disk_storage_pool = "proxmox-nfs"
vm_disk_type = "virtio"
vm_disk_size = "10G"

vm_cpu_cores = 2
vm_memory = 2048

vm_network_model = "virtio"
vm_network_bridge = "vmbr0"
vm_network_firewall = false

iso_storage_pool = "proxmox-nfs"

packer_bind_address = null
packer_bind_port = 8800
packer_ssh_timeout = "30m"

http_ip = "10.10.10.206"

http--user-data-pkrtpl

#cloud-config
autoinstall:
  version: 1
  locale: en_US.UTF-8
  refresh-installer:
    update: yes
  updates: all
  identity:
    hostname: ${hostname}
    realname: ${username}
    username: ${username}
    # plain_text_passwd: ansible  ## mkpasswd -m sha-512
    password: ${password}
  ssh:
    install-server: true
    allow-pw: true
    authorized-keys:
      - ${ssh_key}
  packages:
    - cloud-init
    - qemu-guest-agent
    - sudo
    - tmux
    - vim
  apt:
    #preserve_sources_list: false
    #mirror-selection:
    #    primary:
    #        - country-mirror
    #        - arches: [i386, amd64]
    #          uri: "http://archive.ubuntu.com/ubuntu"
    #fallback: abort
    geoip: true
  storage:
    layout:
      name: direct
  late-commands:
    - echo '${username} ALL=(ALL) NOPASSWD:ALL' > /target/etc/sudoers.d/${username}
  user-data:
    disable_root: false
    timezone: America/Los_Angeles

Makefile

.PHONY: ubuntu2404

ubuntu2404:
	packer init .
	packer build -var-file config/accounts.pkr.hcl -var-file config/proxmox.pkr.hcl -var-file config/vm.pkr.hcl -var-file config/ubuntu-2404.pkr.hcl -force ubuntu-2404/

packer.pkl.hcl

# Packer Template to create an Ubuntu Server on Proxmox
packer {
  required_plugins {
    proxmox = {
      version = "~> 1"
      source  = "github.com/hashicorp/proxmox"
    }
  }
}

# Variable Definitions
variable "proxmox_host" {
    type = string
}

variable "proxmox_api_token_id" {
    type = string
    #default = env("PROXMOX_API_TOKEN_ID")
}

variable "proxmox_api_token_secret" {
    type = string
    sensitive = true
    default   = env("PKR_VAR_PROXMOX_PACKER_TOKEN")

    validation {
        condition     = length(var.proxmox_api_token_secret) > 0
        error_message = "The Packer Token for authenticating API calls in Proxmox is required."
    }
}

variable "proxmox_node" {
    type = string
    default = "s2"
}

variable "vm_id" {
    type = number
    default = null
}

variable "vm_name" {
    type = string
    default = "ubuntu-server-24.04-template"
}

variable "iso_storage_pool" {
    type = string
    default = "local"
}

variable "iso_file" {
    type = string
    default = "ubuntu-24.04.1-live-server-amd64.iso"
}
variable "iso_checksum" {
  type    = string
  default = "file:http://releases.ubuntu.com/24.04/SHA256SUMS"
}

variable "vm_scsi_controller" {
    description = "The SCSI controller model to emulate. Can be lsi, lsi53c810, virtio-scsi-pci, virtio-scsi-single, megasas, or pvscsi."
    type = string
    default = "lsi"
}

variable "vm_disk_size" {
    type = string
    default = "80G"
}

variable "vm_disk_io_thread" {
    description = "Create one I/O thread per storage controller, rather than a single thread for all I/O. Requires vm_scsi_controller = virtio-scsi-single and a vm_disk_type = scsi or virtio."
    type = bool
    default = false
}

variable "vm_disk_storage_pool" {
    type = string
    default = "local-lvm"

}

variable "vm_disk_type" {
    description = "The type of disk. Can be scsi, sata, virtio or ide."
    type = string
    default = "scsi"
}

variable "vm_disk_format" {
    description = "The format of the file backing the disk. Can be raw, cow, qcow, qed, qcow2, vmdk or cloop."
    type = string
    default = "raw"
}

variable "vm_hostname" {
    description = "The hostname of the VM"
    type = string
    default = "ubuntu-server-2404"
}

variable "vm_cpu_cores" {
    type = number
    default = 2
}

variable "vm_memory" {
    type = number
    default = 2048
}

variable "vm_network_model" {
    type = string
    default = "virtio"
}

variable "vm_network_bridge" {
    type = string
    default = "vmbr0"
}

variable "vm_network_firewall" {
    type = bool
    default = false
}

variable "vm_cloud_init_storage_pool" {
    type = string
    default = "local-lvm"
}

variable "vm_ssh_username" {
    type = string
    default = "root"
}

variable "vm_ssh_password_enc" {
    description = "The encrypted password to use for the user that is created on the image"
    type = string
}


variable "vm_ssh_password" {
    description = "The password to use for SSH authentication. If not set, Packer will use the default SSH agent. Set this to null to use key files"
    type = string
    default = null
}

variable "vm_ssh_private_key_file" {
    description = "The existing private key to use for SSH authentication. If not set, Packer will use the default SSH agent."
    type = string
    default = null
}

variable "vm_ssh_public_key_file" {
    description = "The existing public key to use for SSH authentication."
    type = string
    default = null
}

variable "http_ip" {
    description = "The IP address that Packer will use to serve the HTTP files. By default this is set to null which uses all IP's on the host"
    type = string
    default = null
}

variable "packer_bind_address" {
    description = "The address that Packer will use to serve the HTTP files. By default this is set to null which uses all IP's on the host"
    type = string
    default = null
}

variable "packer_bind_port" {
    description = "The port that Packer will use to serve the HTTP files. By default this is set to 8000"
    type = number
    default = 8000
}

variable "packer_ssh_timeout" {
    description = "The timeout for SSH connections. By default this is set to 20m"
    type = string
    default = "20m"
}

locals {
    build_ts = timestamp()
    iso_path = "${var.iso_storage_pool}:iso/${var.iso_file}"
    template_description = "Ubuntu Server Noble Numbat - Built on ${local.build_ts}"
    iso_url = "https://releases.ubuntu.com/24.04/${var.iso_file}"

}

# Resource Definiation for the VM Template
source "proxmox-iso" "ubuntu-2404" {
    # Proxmox Connection Settings
    proxmox_url = "https://${var.proxmox_host}/api2/json"
    username = "${var.proxmox_api_token_id}"
    token = "${var.proxmox_api_token_secret}"
    # (Optional) Skip TLS Verification
    insecure_skip_tls_verify = true

    # VM General Settings
    node = "${var.proxmox_node}"
    vm_id = "${var.vm_id}"
    vm_name = "${var.vm_name}"
    template_description = "${local.template_description}"

    # VM ISO Settings
    iso_url = local.iso_url # TODO: Warning: 'iso_url' is deprecated and will be removed in a future release, define the boot iso options in a 'boot_iso' block
    iso_checksum = "${var.iso_checksum}" # TODO: Warning: 'iso_checksum' is deprecated and will be removed in a future release, define the boot iso options in a 'boot_iso' block
    iso_storage_pool = "${var.iso_storage_pool}" # TODO: Warning: 'iso_storage_pool' is deprecated and will be removed in a future release, define the boot iso options in a 'boot_iso' block
    unmount_iso = true # TODO: Warning: 'unmount_iso' is deprecated and will be removed in a future release, define the boot iso options in a 'boot_iso' block


    # VM Hard Disk Settings
    scsi_controller = "${var.vm_scsi_controller}"

    disks {
        disk_size = "${var.vm_disk_size}"
        storage_pool = "${var.vm_disk_storage_pool}"
        type = "${var.vm_disk_type}"
        format = "${var.vm_disk_format}"
    }

    # VM CPU Settings
    cores = "${var.vm_cpu_cores}"

    # VM Memory Settings
    memory = "${var.vm_memory}"

    # VM Network Settings
    network_adapters {
        model = "${var.vm_network_model}"
        bridge = "${var.vm_network_bridge}"
        firewall = "${var.vm_network_firewall}"
    }

    serials = [ "socket" ]

    # VM Cloud-Init Settings
    cloud_init = false


    boot_command = ["e<wait><down><down><down><end> autoinstall 'ds=nocloud;s=http://{{ .HTTPIP }}:{{ .HTTPPort }}/'<F10>"]
    boot_wait    = "10s"

    # PACKER Autoinstall Settings
    #http_directory = "${path.root}/http"
    http_content = {
        "/user-data" = templatefile("http/user-data.pkrtpl",
            {
                hostname = var.vm_hostname,
                username = var.vm_ssh_username,
                password = var.vm_ssh_password_enc,
                ssh_key  = file(var.vm_ssh_public_key_file)
            }
        )
        "/meta-data" = ""
    }
    # This creates a webserver on all IP's of the computer RUNNING packer to serve
    # the cloud-init files for autoinstall
    #http_bind_address = "0.0.0.0"
    http_port_min = "${var.packer_bind_port}"
    http_port_max = "${var.packer_bind_port}"

    ssh_username = "${var.vm_ssh_username}"
    ssh_private_key_file = "${var.vm_ssh_private_key_file}"
    ssh_timeout = "${var.packer_ssh_timeout}"
}

# Build Definition to create the VM Template
build {

  name = "ubuntu-server-jammy"
  sources = ["source.proxmox-iso.ubuntu-2404"]

  # Wait for cloud-init to finish
  # clean up the instance
  # reset the machine-id
  # remove the SSH host keys
  # sync all disk writes
  # disable the ubuntu user created for provisioning.
  provisioner "shell" {
    inline = [
      "while [ ! -f /var/lib/cloud/instance/boot-finished ]; do echo 'Waiting for cloud-init...'; sleep 1; done",
      "sudo cloud-init clean",
      "sudo rm /etc/ssh/ssh_host_*",
      "sudo truncate -s 0 /etc/machine-id",
      "sudo sync",
      "sudo passwd -d ubuntu"
    ]
  }

  # Copy the cloud-init pve config file to the vm's /tmp
  # (we are ssh as a normal user and not root,
  # so we can't write to /etc/cloud/cloud.cfg.d/99-pve.cfg directly)
  provisioner "file" {
    source = "${path.root}/files/99-pve.cfg"
    destination = "/tmp/99-pve.cfg"
  }

  # Move the cloud-init pve config file to the vm's /etc/cloud/cloud.cfg.d/99-pve.cfg
  provisioner "shell" {
    inline = [ "sudo mv /tmp/99-pve.cfg /etc/cloud/cloud.cfg.d/99-pve.cfg" ]
  }
}