packer-config-gen 1.3

Tool to generate Packer configurations from YAML and Jinja2

packer-config-gen

packer-config-gen (pcg) streamlines your golden image pipeline by separating data (YAML) from build logic (Jinja2). It serves as an orchestration layer that takes clean, inheritable VM specifications and automatically renders:

1. Complex Packer manifests (.pkr.hcl).
2. OS autoinstall configurations (Ubuntu autoinstall, Preseed, Kickstart).

Define your infrastructure once in YAML, and let pcg handle the boilerplate.

Prerequisites

• Python 3.13

Installation

Available on PyPI

pip install packer-config-gen

Usage

The tool expects the following structure in your working directory:

.
├── .env                    # Secrets (SSH_PASS, API_TOKEN)
├── configs/
│   ├── hypervisor.yaml     # General settings (Proxmox/vSphere/VirtualBox)
│   └── os/
│       └── ubuntu.yaml  # OS-specific settings
├── templates/
│   ├── hypervisor.pkr.hcl.j2  # Main Packer template
│   └── subiquity/             # Installer template folder
│       ├── user-data.j2
│       └── meta-data.j2
└── artifacts/              # Output directory (auto-generated)

Examples of repositories that use this utility:

• https://github.com/serhii9132/packer-vbox-builds
• https://github.com/serhii9132/packer-proxmox-builds
• https://github.com/serhii9132/packer-vmware-builds

1. OS configuration example (configs/os/ubuntu.yaml):

packer_builder_name: "ubuntu"
guest_os_type: "Ubuntu_64"
vm_name: "ubuntu-24.04-lts"

iso_config:
  url: "https://releases.ubuntu.com/noble"
  file: "ubuntu-24.04.3-live-server-amd64.iso"
  checksum: "file:https://releases.ubuntu.com/noble/SHA256SUMS"

boot_command:
  - "e<wait><down><down><down><end><bs><bs><bs><bs><wait>"
  - "ipv6.disable=1 \"ds=nocloud-net;s=http://{{ .HTTPIP }}:{{ .HTTPPort }}/\" autoinstall ---<wait>"
  - "<f10><wait>"

installer: "subiquity"
installer_files:
  - meta-data
  - user-data

2. Environment variables example:

export USERNAME="user"

export PASSWORD='$6$vPP.....'    # Use: mkpasswd -m sha-512

export SSH_PUBLIC_KEY='ssh-ed25519 AAAAbbbbbbbccccccc....'
export SSH_PRIVATE_KEY_FILE="/home/user/.ssh/key"

3. Hypervisor configuration example (configs/hypervisor.yaml)

system_settings:
  cpus: 2
  memory: 2048
  gfx_vram_size: 16
  firmware_type: "efi"
  export_format: "ova"
  communicator: "ssh"
  timezone: ""

vboxmanage_commands:
  - [ "modifyvm", "{{.Name}}", "--audio", "none" ]
  - [ "modifyvm", "{{.Name}}", "--vrde", "off" ]

iso_config:
  interface: "sata"
  source: ".cache/iso" 

disk_config:
  size: 150000
  interface: "sata"
  is_discard: false
  is_nonrotational: false

guest_additions:
  mode: "upload"
  path: "/tmp/VBoxGuestAdditions.iso"

ssh_config:
  username: ""
  password: ""
  private_key_file: ""
  pub_key: ""
  timeout: "30m"

boot_control:
  boot_wait: "5s"
  shutdown_command: "sudo shutdown -P now"

Run the pcg command, passing the OS configuration filename:

pcg --os ubuntu

Result: The following files will be created in the artifacts/ubuntu/ folder:

- ubuntu.pkr.hcl
- cidata/user-data
- cidata/meta-data

Now you can start the build:

packer build artifacts/ubuntu/ubuntu.pkr.hcl

License

MIT