Ubuntu 20.04 autoinstall using PXE Server

Sunday. December 20, 2020 - 2 mins

With Ubuntu 20.04, Canonical switched from the Debian installer to their own autoinstaller. This means that you have to build a new PXEBoot environment.

Before you start, you need to have:

Working TFTP Server
Working HTTP Server
Working DHCP Server

I’m not going to show you how to configure TFTP/HTTP/DHCP because there are planty of documentation available on internet. I’m assuming you have all 3 components already setup and running.

Download Ubuntu 20.04 ISO

Download Ubuntu ISO 20.04 from https://releases.ubuntu.com/20.04/ and copy iso file to http web path.

[root@spatel ~]# ls /var/www/html/pxe_repo/ubuntu-20.04.1-live-server-amd64.iso
/var/www/html/pxe_repo/ubuntu-20.04.1-live-server-amd64.iso

TFTP server prep

Mount ISO to /mnt directory to obtain vmlinuz/initrd

[root@spatel pxe_repo]# mount ubuntu-20.04.1-live-server-amd64.iso /mnt
mount: /dev/loop0 is write-protected, mounting read-only

Copy vmlinuz/initrd to tftp path

[root@spatel pxe_repo]# mkdir -p /var/lib/tftpboot/images/ubuntu
[root@spatel pxe_repo]# cp /mnt/casper/vmlinuz /var/lib/tftpboot/images/ubuntu/.
[root@spatel pxe_repo]# cp /mnt/casper/initrd /var/lib/tftpboot/images/ubuntu/.

Unmount ISO

[root@spatel pxe_repo]# umount /mnt

Add following snippet in file /var/lib/tftpboot/pxelinux.cfg/default ( ds=nocloud-net;s=http:// will find user-data file)

LABEL Ubuntu-20.04.1
        kernel /images/ubuntu/vmlinuz
        MENU DEFAULT
        MENU LABEL Ubuntu-20.04.1
        append initrd=/images/ubuntu/initrd ip=dhcp autoinstall url=http://www.spatel.net/pxe_repo/ubuntu-20.04.1-live-server-amd64.iso ds=nocloud-net;s=http://www.spatel.net/pxe_ks/ubuntu-20-04-1/

HTTP server prep.

Create empty meta-data file

[root@spatel ~]# touch /var/www/html/pxe_ks/ubuntu-20-04-1/meta-data

Create user-data file which contain all installation instruction in yaml style

[root@spatel ~]# cat /var/www/html/pxe_ks/ubuntu-20-04-1/user-data
#cloud-config
autoinstall:
  version: 1
  apt:
    geoip: true
    preserve_sources_list: false
    primary:
    - arches: [amd64, i386]
      uri: http://us.archive.ubuntu.com/ubuntu
    - arches: [default]
      uri: http://ports.ubuntu.com/ubuntu-ports
  identity:
    hostname: ubuntu-server
    password: $6$wjbhAd/wF1HKn7V.$W8IIgNtvQCu1L90XXvZahP9Lm2ILPF/juY.ExliRbpyXclEyBTK1F3u1FJdWGL0HnNPwThorz/
    username: ubuntu
  keyboard: {layout: us, toggle: null, variant: ''}
  locale: en_US
  network:
    version: 2
    ethernets:
      bootif:
        critical: true
        dhcp-identifier: mac
        dhcp4: true
        nameservers:
          addresses: [8.8.8.8]
          search: [spatel.net]
  ssh:
    allow-pw: true
    authorized-keys: []
    install-server: true

  storage:
    #### Don't create /root/swap.img file
    swap:
      size: 0
    config:
    #### prep system disks
    - type: disk
      id: disk-sda
      path: /dev/sda
      preserve: false
      wipe: superblock-recursive
      ptable: gpt
      grub_device: true
     #### disk partitions
    - type: partition
      number: 1
      id: bios_boot_part   # required by GRUB on first disk
      size: 1MB
      device: disk-sda
      flag: bios_grub
    - type: partition
      number: 2
      id: boot_part       # /boot partition
      size: 1G
      device: disk-sda
      preserve: false
    - type: partition
      number: 3
      id: lvm_part        # add remaining space to LVM
      size: -1
      device: disk-sda
      preserve: false
     #### LVM volume group and logical volumes
    - type: lvm_volgroup
      id: vg0
      name: vg0
      devices:
        - lvm_part
    - type: lvm_partition
      id: lvm_swap        # create swap partition on lvm
      volgroup: vg0
      name: swap
      size: 8G
    - type: lvm_partition
      id: lvm_root        # create / partition on lvm, all available space
      volgroup: vg0
      name: root
      size: -1
    #### Format the filesystems
    - type: format
      id: fs_boot_part
      fstype: ext4
      volume: boot_part
    - type: format
      id: fs_root
      fstype: ext4
      volume: lvm_root
    - type: format
      id: fs_swap
      fstype: swap
      volume: lvm_swap
    #### Mount the filesystems
    - type: mount
      id: mount_boot
      device: fs_boot_part
      path: /boot
    - type: mount
      id: mount_root
      device: fs_root
      path: /
    - type: mount
      id: mount_swap
      device: fs_swap
      path: none
  #### POST Install commands
  late-commands:   
    - sed -i 's/#PermitRootLogin prohibit-password/PermitRootLogin yes/' /target/etc/ssh/sshd_config
    - sed -i 's|^root:.:|root:$6$wjbhAd/wF1HKn7V.$W8IIgNtvQCu1L90XXvZahP9Lm2ILPF/juY.ExliRbpyXclEyBTK1F3u1FJdWGL0HnNPwThorz/:|' /target/etc/shadow
    - curtin in-target --target=/target -- apt-get purge -y snapd

You’re ready for pxe boot your ubunut 20.04. Enjoy!

Ubuntu 20.04 autoinstall using PXE Server

Download Ubuntu 20.04 ISO

TFTP server prep

HTTP server prep.

Related Posts