Build a disk template

§ 1Purpose

Produce a sealed, reusable qcow2 image in the local store from installer media.

§ 2Prerequisites

A template {} block exists in vmlab.wcl (or a file passed with -f).
Its source (ISO/qcow2/template/scratch) is reachable; URL sources have a sha256.

§ 3Flowchart

§ 4Steps

§ 4.11

§ 4.2Define the template

wcl

template "linux-modern" {
  arch = "x86_64"  version = "1.0"  profile = "linux-modern"  disk = 20GiB
  source "iso" { url = "https://.../x.iso" sha256 = "abc123..." }
  media { kind = "iso" from = "./cloudinit/" label = "CIDATA" }
  nic { nat = true }
  provision "scripts/install.ws" { }   // drives the installer; installs the guest agent
}

Declare arch, version, profile and the working disk size, exactly one source block, any build media/disks/NIC, and a provision script that drives the installer and installs the QEMU guest agent.

§ 4.32

§ 4.4Build

console

$ vmlab template build
$ vmlab template build -f templates.wcl linux-modern   # one named template

Run vmlab template build. vmlab resolves the source (downloads cached + content-addressed), boots a one-VM build lab, runs the provision, then shuts down, flattens and seals into the store. A failed build leaves nothing behind.

§ 4.53

§ 4.6Confirm it sealed

console

$ vmlab template list

vmlab template list should show x86_64/linux-modern@1.0. Reference it from a lab as template = "x86_64/linux-modern".

Verification

vmlab template list shows the new <arch>/<name>@<version> ref, and a lab VM referencing it passes vmlab validate.