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How to build the OS2borgerPC Kiosk ISO image (x64)

In order to build the ISO image, use a Ubuntu 20.04 Server Edition installation CD and basically follow the instructions on this page:

https://gist.github.com/s3rj1k/55b10cd20f31542046018fcce32f103e

For more info about autoinstall, see this page:

https://ubuntu.com/server/docs/install/autoinstall

Basically, go to the directory where you wish to build the ISO, get the installation ISO and unpack it:

wget http://releases.ubuntu.com/focal/ubuntu-20.04.1-live-server-amd64.iso

# Extract ISO:
mkdir iso
7z x ubuntu-20.04.1-live-server-amd64.iso -oiso
rm -rf 'iso/[BOOT]/'
cp -r /path/to/image/ubuntu-image/* iso

md5sum iso/.disk/info > iso/md5sum.txt
sed -i 's|iso/|./|g' iso/md5sum.txt

Now you can make any modifications you want, e.g. to the install process in nocloud/user-data or to the boot instructions in isolinux or boot/grub.

Special customizations are best handled through late_commands in nocloud/user-data.

If you need to include extra packages in the ISO, one way to do it is to include the packages (.deb files) in a bespoke directory in the ISO and install them directly with dpkg -i, either in a late_command or using a script.

The wifi_setup script currently expect such packages to exist in the directory scripts/wifi - as we need to be able to set up wifi without a network connection, while we should, at the same time, never enable wifi unless we know that it’s necessary.

Alternatively, you could make them officially part of the image by adding them in pool/extras. This, however, requires you to unsquash the embedded squashfs file system, update the package lists, re-squash it and sign it. You must also compile a new version of the ubuntu-keyring package to include your own GPG signing key.

If you need to do this, you can find instructions on doing so here:

https://help.ubuntu.com/community/InstallCDCustomization

If you did add debs to pool/extras, please note:

  • To generate a new filesystem.squashfs, you must first unpack it with unsquashfs - the directory you get from that is where you put the updated keyrings.

  • Delete the old filesystem.squashfs before rebuilding it with mksquashfs, otherwise your changes are written to new paths with “_1” appended.

  • Do not worry about dpkg-scanpackages, just follow the instructions for apt-ftparchive and you’re good.

Once you’re ready to create the ISO image for installation, run:

xorriso -as mkisofs -r   -V os2borgerpc_kiosk   -o os2borgerpc_kiosk-1.0.0rc1.iso   -J -l -b isolinux/isolinux.bin -c isolinux/boot.cat -no-emul-boot   -boot-load-size 4 -boot-info-table   -eltorito-alt-boot -e boot/grub/efi.img -no-emul-boot   -isohybrid-gpt-basdat -isohybrid-apm-hfsplus   -isohybrid-mbr /usr/lib/ISOLINUX/isohdpfx.bin iso/boot iso

where “os2borgerpc_kiosk” and “os2borgerpc_kiosk-1.0.0rc1.iso” should be replaced by what you wish the tag and filename of the ISO image to be.

You’ll need to install the necessary dependencies to create the ISO - on Ubuntu 20.04, it can be done with:

sudo apt-get install xorriso isolinux