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Packer plugin

Introduction​

Packer automates the creation of machine images: describe an image once in code, and rebuild it identically whenever needed. In an XCP-ng/Xen Orchestra environment, that means building golden VM templates (base OS, updates, guest tools, your provisioning) instead of preparing them by hand.

Vates maintains the XenServer Packer plugin, a builder that installs an OS from an ISO on an XCP-ng host and turns the result into a reusable image. It was revived from an abandoned upstream project and is developed alongside the Terraform provider to ensure interoperability: templates built with Packer can then be cloned into VMs through the Terraform provider, the REST API, or the Xen Orchestra web interface.

note

The plugin talks directly to an XCP-ng host (via XAPI and SSH), not to the Xen Orchestra API. You point it at a host with its credentials; Xen Orchestra then sees and manages the resulting templates like any other.

Installation​

Declare the plugin in your template and let packer init download it:

packer {
  required_plugins {
    xenserver = {
      version = ">= v0.9.0"
      source  = "github.com/vatesfr/xenserver"
    }
  }
}
download the declared plugins
# packer init .
tip

Version 0.9.0 and later are validated against XCP-ng 8.3. Check the releases page for the current version.

Minimal example​

The plugin provides the xenserver-iso builder: it creates a VM on the target host, boots it from an ISO, runs the OS installation, then captures the result. A skeleton looks like this:

source "xenserver-iso" "example" {
  # The XCP-ng host to build on
  remote_host     = "your-xcpng-host"
  remote_username = "root"
  remote_password = "your-password"

  # Installation media and VM shape
  iso_url      = "https://example.com/path/to/installer.iso"
  iso_checksum = "sha256:..."
  sr_name      = "Local storage"
  vm_name      = "packer-golden-image"
  vm_memory    = 4096
  disk_size    = 20480

  # How Packer connects to the VM to provision it
  ssh_username = "packer"
  ssh_password = "your-vm-password"
}

build {
  sources = ["xenserver-iso.example"]
}
build the image
# packer build .

A real template also needs the OS installer automated (kickstart, preseed, or cloud-init autoinstall, served to the VM during boot). Rather than duplicating that here, start from the maintained, complete Ubuntu example in the plugin repository.

Going further​

The plugin repository is the source of truth for the builder's options (ISO handling, storage and network selection, output formats, HTTP-served install files, and so on), its examples, and its releases. See also the Packer documentation for general concepts like provisioners and variables.