How to Generate a UKI Image for HTTPBoot with Gardenlinux

Step 1: Prerequisites

• Ensure you have the ukify tool installed on your system. This tool is essential for creating the UKI image.
• You will need administrative or root privileges to execute most of the commands described.

Step 2: Download and Prepare Gardenlinux Release

1. Download the appropriate Gardenlinux release for your architecture. For example, a metal-based system with an AMD64 architecture, use the following command:

   wget https://github.com/gardenlinux/gardenlinux/releases/download/1443.10/metal-gardener_prod_pxe-amd64-1443.10-8d098305.tar.xz

2. Extract the downloaded .tar.xz file:

   tar -xvf metal-gardener_prod_pxe-amd64-1443.10-8d098305.tar.xz

3. Further extract the nested *.pxe.tar.gz which contains the kernel and initial RAM disk:

   tar -xzf <nested_tar_name>.pxe.tar.gz

   You should see files like vmlinuz, initrd, and root.squashfs.

Step 3: Obtain the Bootloader Stub

Download the EFI stub required for the UKI creation:

tbd

Step 4: Create the UKI Image

Construct the UKI image using the ukify command. Ensure to replace placeholders with actual paths and URLs:

ukify build --stub "/path/to/stub" --linux "/path/to/vmlinuz" --initrd "/path/to/initrd" --cmdline "@cmdline" --output "/path/to/output/test.uki"

# Create file with the name cmdline, with following content
# Use this as the sample command line, replace URLs and paths as necessary
initrd=/path/to/initrd gl.ovl=/:tmpfs gl.live=1 ip=dhcp console=ttyS0,115200 console=tty0 earlyprintk=ttyS0,115200 consoleblank=0 ignition.firstboot=1 ignition.config.url=IGNITION_URL ignition.platform.id=metal gl.url=SQUASHFS_URL

Step 5: Deploy the Image to a Server

Copy the created test.uki to an Nginx server configured to serve the files:

cp /path/to/output/test.uki /path/to/nginx/server/httpboot/test-uki.efi
# Also, ensure the squashfs file is accessible via HTTP
cp /path/to/root.squashfs /path/to/nginx/server/httpboot/squashfs

Ensure EFI files are served by NGINX with the correct content-type.

 application/efi efi;

Step 6: Configure HTTPBoot

Create a YAML configuration for the HTTPBoot client. Replace placeholders as required:

apiVersion: boot.ironcore.dev/v1alpha1
kind: HTTPBootConfig
metadata:
  name: httpbootconfig-sample
  namespace: boot-operator-system
spec:
  ignitionSecretRef:
    name: ignition-http-sample
    namespace: boot-operator-system
  systemUUID: "generate-this-uuid"
  systemIPs:
    - "1.1.1.1"
    - "ip/mac-address-of-interfaces"
  ukiURL: "http://[your-server-ip-or-domain]/httpboot/test-uki.efi"

Apply this configuration to your cluster and ensure the metal machine is set to boot via HTTPBoot.