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Deploying Ubuntu

This guide walks through the process of deploying Ubuntu from either an operating system image or a Docker image.

Using an Operating System Image

Ubuntu is distributed in a number of different formats, which are all available on the cloud-images site.

This example uses the image with the .img extension.

focal-server-cloudimg-amd64.img     2021-03-11 22:27  528M  Ubuntu Server 20.04 LTS (Focal Fossa) daily builds

This image is actually a qcow2 filesystem image and is a full disk image including partition tables, partitions filled with filesystems and the files, and importantly, a boot loader at the beginning of the disk image.

Converting Image

In order to use this image, it needs to be converted into a raw filesystem. In order to do the conversion, install the qemu-img CLI tool.

apt-get install -y qemu-utils

Then, use the tool to convert the image into a raw filesystem.

qemu-img convert  ./focal-server-cloudimg-amd64.img -O raw ./focal-server-cloudimg-amd64.raw

Optional - You can compress this raw image to save on both local disk space and network bandwidth when deploying the image.

gzip ./focal-server-cloudimg-amd64.raw

Move the raw image to a locally accessible web server. To simplify, you can place the image in the Tinkerbell sandbox webroot, which allows access to the image at the IP address of the tink-server.

mv ./focal-server-cloudimg-amd64.raw ./sandbox/deploy/state/webroot`

Creating the Template

The template uses actions from the Artifact Hub.

  • image2disk - to write the OS image to a block device.
  • kexec - to kexec into our newly provisioned operating system.

Important: Don't forget to pull, tag, and push quay.io/tinkerbell-actions/image2disk:v1.0.0 prior to using it.

version: "0.1"
name: Ubuntu_Focal
global_timeout: 1800
tasks:
  - name: "os-installation"
    worker: "{{.device_1}}"
    volumes:
      - /dev:/dev
      - /dev/console:/dev/console
      - /lib/firmware:/lib/firmware:ro
    actions:
      - name: "stream-ubuntu-image"
        image: quay.io/tinkerbell-actions/image2disk:v1.0.0
        timeout: 600
        environment:
          DEST_DISK: /dev/sda
          IMG_URL: "http://192.168.1.1:8080/focal-server-cloudimg-amd64.raw.gz"
          COMPRESSED: true
      - name: "kexec-ubuntu"
        image: quay.io/tinkerbell-actions/kexec:v1.0.0
        timeout: 90
        pid: host
        environment:
          BLOCK_DEVICE: /dev/sda1
          FS_TYPE: ext4

File System Images

Note that it is also possible to install Ubuntu from the compressed filesystem image.

focal-server-cloudimg-amd64.tar.gz  2021-03-11 22:30  485M  File system image and Kernel packed

This filesystem image is typically an ext4 filesystem that contains all of the files in a partition for Ubuntu to run. However, in order for us to use this image we would need to:

  • Partition the disk
  • Write this data to the partition
  • Install a boot loader

With all of this in mind, it becomes much simpler to convert the qcow2 image and simply write it to disk.

Using a Docker Image

We can easily make use of the official Docker images to generate a root filesystem for use when deploying with Tinkerbell.

Downloading the Image

TMPRFS=$(docker container create ubuntu:latest)
docker export $TMPRFS > ubuntu_rootfs.tar
docker rm $TMPRFS

Optional - You can compress this raw image to save on both local disk space and network bandwidth when deploying the image.

gzip ./ubuntu_rootfs.tar

Move the raw image to a locally accessible web server. To simplify, you can place the image in the Tinkerbell sandbox webroot, which allows access to the image at the IP address of the tink-server.

mv ./ubuntu_rootfs.tar.gz ./sandbox/deploy/state/webroot

Creating the Template

The template makes use of the actions from the artifact hub.

  • rootio - to partition our disk and make filesystems.
  • archive2disk - to write the OS image to a block device.
  • cexec - to run commands inside (chroot) our newly provisioned operating system.
  • kexec - to kexec into our newly provisioned operating system.
version: "0.1"
name: ubuntu_provisioning
global_timeout: 1800
tasks:
  - name: "os-installation"
    worker: "{{.device_1}}"
    volumes:
      - /dev:/dev
      - /dev/console:/dev/console
      - /lib/firmware:/lib/firmware:ro
    actions:
      - name: "disk-wipe-partition"
        image: quay.io/tinkerbell-actions/rootio:v1.0.0
        timeout: 90
        command: ["partition"]
        environment:
            MIRROR_HOST: 192.168.1.2
      - name: "format"
        image: quay.io/tinkerbell-actions/rootio:v1.0.0
        timeout: 90
        command: ["format"]
        environment:
            MIRROR_HOST: 192.168.1.2
      - name: "expand-ubuntu-filesystem-to-root"
        image: quay.io/tinkerbell-actions/archive2disk:v1.0.0
        timeout: 90
        environment:
            ARCHIVE_URL: http://192.168.1.1:8080/ubuntu_rootfs.tar.gz
            ARCHIVE_TYPE: targz
            DEST_DISK: /dev/sda3
            FS_TYPE: ext4
            DEST_PATH: /
      - name: "install-grub-bootloader"
        image: quay.io/tinkerbell-actions/cexec:v1.0.0
        timeout: 90
        environment:
            BLOCK_DEVICE: /dev/sda3
            FS_TYPE: ext4
            CHROOT: y
            CMD_LINE: "grub-install --root-directory=/boot /dev/sda"
      - name: "kexec-ubuntu"
        image: quay.io/tinkerbell-actions/kexec:v1.0.0
        timeout: 600
        environment:
          BLOCK_DEVICE: /dev/sda3
          FS_TYPE: ext4