Comment 2 for bug 1803667

Right now if i need unattended install, I need to customize the official iso
1.take install guestOS with ubuntu-18.10-desktop-amd64.iso as a example:
  if I need unattended installation with ubuntu-18.10-desktop-amd64.iso, I need to uncompress the
  iso, modify boot parameter in file boot/grub/grub.cfg and modify file preseed/ubuntu.preseed,
  and then make a new iso.

2.take install guestOS with ubuntu-18.10-live-server-amd64.iso as a example:
  if I need unattended installation with ubuntu-18.10-live-server-amd64.iso,
  I take the following step:
  1)download the example file of answers.yaml at here
    https://github.com/CanonicalLtd/subi...s/answers.yaml

  2) unsquash the file casper/filesystem.squashfs in the ubuntu-18.10-live-server-amd64.iso,
     and get the folder " squashfs-root", then mkdir subiquity_config in the folder of
     squashfs-root

  3) copy the answers.yaml into the squashfs-root/subiquity_config/

  4) repacking the folder squashfs-root into filesystem.squashfs by using mksquashfs command,
     and repacking the ubuntu-18.10-live-server-amd64.iso by using genisoimage command to
     make iso.

Expect for unattended install:
  1) don't do any change to official iso. when start to install OS, the installer can support to
scan the other CD/DVD to get the config file for unattended install.

Expected steps:
  1) mount official iso(such as ubuntu-18.10-desktop-amd64.iso) to CD/DVD
  2) mount another iso which only include config file for unattended install to another CD/DVD.
  3) power on and the installer start to run
  4) the installer can scan the others CD/DVD and get the config file. It will install OS and config OS automatically without any input.

Thanks.

best regards
Yuhua Zou