Ported the bootable image creation to 24

.github/workflows/build-image.yaml

@@ -16,17 +16,24 @@ jobs:
           submodules: true
       - name: Install build dependencies
         run: |
-          sudo apt install -y make squashfs-tools dosfstools mtools
+          sudo apt install -y make squashfs-tools dosfstools mtools xorriso grub-common grub-pc-bin
           sudo snap refresh --edge snapd
           sudo snap install --classic ubuntu-image
       - name: Build image
         run: |
           make
-      - name: Upload artifacts
+      - name: Upload image artifact
         uses: actions/upload-artifact@v4
         with:
-          name: image
+          name: bootable-image
           path: |
             README.md
-            *.tar.gz
-          compression-level: 0 # content is already compressed
+            *.img.xz
+          compression-level: 0
+      - name: Upload ISO artifact
+        uses: actions/upload-artifact@v4
+        with:
+          name: bootable-iso
+          path: |
+            *.iso
+          compression-level: 6

Makefile

@@ -1,19 +1,23 @@
 
 EXTRA_SNAPS =
 ALL_SNAPS = $(EXTRA_SNAPS) firefox
-all: pc.tar.gz
+all: bootable-iso
+
+bootable-iso: ubuntu-core-desktop-24-amd64.iso
+bootable-iso-dangerous: ubuntu-core-desktop-24-dangerous-amd64.iso
+
+define build_img =
+rm -rf img${1}
+ubuntu-image snap --output-dir img${1} --image-size ${2}G \
+  $(foreach snap,$(ALL_SNAPS),--snap $(snap)) $<
+mv img${1}/${3}.img ./$@
+endef
 
 pc.img: ubuntu-core-desktop-24-amd64.model $(EXTRA_SNAPS)
-	rm -rf img/
-	ubuntu-image snap --output-dir img --image-size 20G \
-	  $(foreach snap,$(ALL_SNAPS),--snap $(snap)) $<
-	mv img/pc.img .
+	$(call build_img,,20,pc)
 
 pc-dangerous.img: ubuntu-core-desktop-24-amd64-dangerous.model $(EXTRA_SNAPS)
-	rm -rf dangerous/
-	ubuntu-image snap --output-dir dangerous --image-size 20G \
-	  $(foreach snap,$(ALL_SNAPS),--snap $(snap)) $<
-	mv dangerous/pc.img pc-dangerous.img
+	$(call build_img,-dangerous,20,pc)
 
 pi.img: ubuntu-core-desktop-22-pi.model $(EXTRA_SNAPS)
 	rm -rf dangerous/
@@ -29,10 +33,43 @@ pi-dangerous.img: ubuntu-core-desktop-22-pi-dangerous.model $(EXTRA_SNAPS)
 %.tar.gz: %.img
 	tar czSf $@ $<
 
+%.img.xz: %.img
+	xz -k --force --threads=0 -vv $<
+
 .PHONY: all
 
+define build_bootable_img =
+rm -rf output/
+mkdir -p image
+cat image_data/install-sources.yaml.in |sed "s/@FILE@/$</g"|sed "s/@SIZE@/$(shell stat -c%s $<)/g" > image/install-sources.yaml
+cat image_data/core-desktop.yaml.in |sed "s/@FILE@/$</g" | sed "s/@OUTPUT@/$@/g" > image/core-desktop.yaml
+sudo ubuntu-image classic --debug -O output/ image/core-desktop.yaml
+sudo chown -R $(shell id -u):$(shell id -g) output
+mv output/$@ .
+endef
+
+ubuntu-core-desktop-24-amd64.img: pc.img.xz image_data/core-desktop.yaml.in image_data/install-sources.yaml.in
+	$(call build_bootable_img)
+
+ubuntu-core-desktop-24-dangerous-amd64.img: pc-dangerous.img.xz image_data/core-desktop.yaml.in image_data/install-sources.yaml.in
+	$(call build_bootable_img)
+
+ubuntu-core-desktop-24-%.iso: ubuntu-core-desktop-24-%.img
+	./create_iso.sh $<
+
 clean:
 	sudo rm -rf img
 	sudo rm -rf output
 	sudo rm -rf image
+	sudo rm -rf image2
+	sudo rm -rf img-dangerous
+	sudo rm -rf livecd-rootfs
 	sudo rm -f pc*.img.xz pc*.img pc*.tar.gz ubuntu-core-desktop-*.img ubuntu-core-desktop-*.img.xz ubuntu-core-desktop-*.iso image/install-sources.yaml
+
+clean-bootable:
+	sudo rm -rf img
+	sudo rm -rf output
+	sudo rm -rf image
+	sudo rm -rf image2
+	sudo rm -rf img-dangerous
+	sudo rm -f ubuntu-core-desktop-*.img ubuntu-core-desktop-*.img.xz ubuntu-core-desktop-*.iso image/install-sources.yaml image/core-desktop.yaml

README.md

@@ -1,8 +1,12 @@
 # GDM on Ubuntu Core
 
-This directory contains an image of Ubuntu Core 22 with the GDM
-display manager loaded into the boot file system.  It can be launched
-in a Qemu virtual machine by following these instructions:
+This directory contains an image of Ubuntu Core 24 with the GDM
+display manager loaded into the boot file system, and an ISO image
+with an installer for that same image.
+
+The ISO image can be used in any virtual machine. The image, in .zx
+compressed format, can be launched in a Qemu virtual machine by
+following these instructions:
 
 1. Download and decompress the two image files and place them in the
    same directory.

create_iso.sh

@@ -0,0 +1,134 @@
+#!/bin/sh
+
+# Process obtained from https://itnext.io/how-to-create-a-custom-ubuntu-live-from-scratch-dd3b3f213f81
+
+# we expect a .xz compressed image (see below where we decompress it)
+ORIGINAL_DISK_IMAGE=$1
+DISK_IMAGE=$PWD/output/disk.img
+
+# where to mount the disk image
+CHROOT=$PWD/output/mnt
+
+cp -a ${ORIGINAL_DISK_IMAGE} ${DISK_IMAGE}
+
+#cd output
+# decompress the image
+#xz -v -d ${DISK_IMAGE}
+#cd ..
+
+mkdir -p $CHROOT
+# since we know that the partition with the data is the third one, we use awk to extract the start sector
+sudo mount -o loop,offset=$(expr 512 \* $(fdisk -l ${DISK_IMAGE} |grep img3 | awk '{print $2}')) ${DISK_IMAGE} $CHROOT
+
+# we prepare the chroot environment to ensure that everything works inside..
+sudo mount -o bind /dev ${CHROOT}/dev
+sudo mount -o bind /dev/pts ${CHROOT}/dev/pts
+sudo mount -o bind /proc ${CHROOT}/proc
+sudo mount -o bind /sys ${CHROOT}/sys
+sudo mount -o bind /run ${CHROOT}/run
+# install the required packages
+sudo chroot ${CHROOT} apt install -y casper
+# and, if needed, open a bash shell to do manual checks
+# chroot ${CHROOT} /bin/bash
+sudo umount ${CHROOT}/run
+sudo umount ${CHROOT}/sys/firmware/efi/efivars
+sudo umount ${CHROOT}/sys
+sudo umount ${CHROOT}/proc
+sudo umount ${CHROOT}/dev/pts
+sudo umount ${CHROOT}/dev
+
+rm -rf $PWD/image2
+
+mkdir -p $PWD/image2/casper
+mkdir -p $PWD/image2/isolinux
+mkdir -p $PWD/image2/install
+
+mv $CHROOT/cdrom/casper/* $PWD/image2/casper/
+
+sudo cp $CHROOT/boot/vmlinuz-**-**-generic image2/casper/vmlinuz
+sudo cp $CHROOT/boot/initrd.img-**-**-generic image2/casper/initrd
+
+touch image2/ubuntu
+
+cat <<EOF > image2/isolinux/grub.cfg
+
+search --set=root --file /ubuntu
+
+insmod all_video
+
+set default="0"
+set timeout=3
+
+menuentry "Install Ubuntu Core Desktop" {
+   linux /casper/vmlinuz boot=casper quiet splash ---
+   initrd /casper/initrd
+}
+EOF
+
+sudo mksquashfs $CHROOT image2/casper/filesystem.squashfs
+
+printf $(sudo du -sx --block-size=1 $CHROOT | cut -f1) > image2/casper/filesystem.size
+
+# we are done with the original disk image
+#sudo umount ${CHROOT}/sys/firmware/efi/efivars
+#sudo umount ${CHROOT}/sys
+sudo umount ${CHROOT}
+rmdir ${CHROOT}
+
+cd $PWD/image2
+
+grub-mkstandalone \
+   --format=x86_64-efi \
+   --output=isolinux/bootx64.efi \
+   --locales="" \
+   --fonts="" \
+   "boot/grub/grub.cfg=isolinux/grub.cfg"
+
+(
+   cd isolinux && \
+   dd if=/dev/zero of=efiboot.img bs=1M count=10 && \
+   sudo mkfs.vfat efiboot.img && \
+   LC_CTYPE=C mmd -i efiboot.img efi efi/boot && \
+   LC_CTYPE=C mcopy -i efiboot.img ./bootx64.efi ::efi/boot/
+)
+
+grub-mkstandalone \
+   --format=i386-pc \
+   --output=isolinux/core.img \
+   --install-modules="linux16 linux normal iso9660 biosdisk memdisk search tar ls" \
+   --modules="linux16 linux normal iso9660 biosdisk search" \
+   --locales="" \
+   --fonts="" \
+   "boot/grub/grub.cfg=isolinux/grub.cfg"
+
+cat /usr/lib/grub/i386-pc/cdboot.img isolinux/core.img > isolinux/bios.img
+
+sudo /bin/bash -c "(find . -type f -print0 | xargs -0 md5sum | grep -v "\./md5sum.txt" > md5sum.txt)"
+
+sudo xorriso \
+   -as mkisofs \
+   -iso-level 3 \
+   -full-iso9660-filenames \
+   -volid "Ubuntu Core Desktop" \
+   -output ${DISK_IMAGE%.*}.iso \
+   -eltorito-boot boot/grub/bios.img \
+      -no-emul-boot \
+      -boot-load-size 4 \
+      -boot-info-table \
+      --eltorito-catalog boot/grub/boot.cat \
+      --grub2-boot-info \
+      --grub2-mbr /usr/lib/grub/i386-pc/boot_hybrid.img \
+   -eltorito-alt-boot \
+      -e EFI/efiboot.img \
+      -no-emul-boot \
+   -append_partition 2 0xef isolinux/efiboot.img \
+   -m "isolinux/efiboot.img" \
+   -m "isolinux/bios.img" \
+   -graft-points \
+      "/EFI/efiboot.img=isolinux/efiboot.img" \
+      "/boot/grub/bios.img=isolinux/bios.img" \
+      "."
+
+cd ..
+mv ${DISK_IMAGE%.*}.iso ${ORIGINAL_DISK_IMAGE%.*}.iso
+rm -rf image2

image_data/06_quiet.cfg

@@ -0,0 +1,4 @@
+output: {all: '>> /var/log/cloud-init-output.log'}
+no_ssh_fingerprints: true
+ssh:
+  emit_keys_to_console: false

image_data/autoinstall.yaml

@@ -0,0 +1,7 @@
+version: 1
+source:
+  id: ubuntu-core-desktop
+  search_drivers: false
+interactive-sections:
+  - locale
+  - storage

image_data/core-desktop.yaml.in

@@ -0,0 +1,96 @@
+name: ubuntu-core-desktop-amd64
+display-name: Ubuntu Core Desktop amd64
+revision: 1
+architecture: amd64
+series: noble
+class: preinstalled
+kernel: linux-image-generic
+gadget:
+  url: "https://git.launchpad.net/~canonical-foundations/snap-pc/+git/github-mirror-amd64"
+  branch: classic
+  type: "git"
+rootfs:
+  components:
+    - main
+    - restricted
+  seed:
+    urls:
+      - "git://git.launchpad.net/~ubuntu-core-dev/ubuntu-seeds/+git/"
+    branch: noble
+    names:
+      - minimal
+customization:
+  cloud-init:
+    user-data: |
+      #cloud-config
+      chpasswd:
+        expire: false
+        users:
+          - name: ubuntu
+            password: ubuntu
+            type: text
+    meta-data: |
+      #cloud-config
+      dsmode: local
+      instance_id: ubuntu-core-desktop
+  extra-packages:
+    - name: squashfs-tools
+    - name: snapd
+    - name: cloud-init
+    - name: lshw
+    - name: bzip2
+    - name: tar
+    - name: lvm2
+    - name: parted
+    - name: dosfstools
+    - name: xz-utils
+    - name: console-setup-linux
+    - name: whois
+    - name: mdadm
+  extra-snaps:
+    - name: subiquity
+    - name: core22
+    - name: snapd
+  manual:
+    make-dirs:
+      - path: /cdrom/casper
+        permissions: 0755
+      - path: /etc/systemd/journald.conf.d
+        permissions: 0755
+      - path: /etc/systemd/system/systemd-journald.service.d
+        permissions: 0755
+      - path: /etc/cloud/cloud.cfg.d
+        permissions: 0755
+    copy-file:
+      - source: install-sources.yaml
+        destination: /cdrom/casper/install-sources.yaml
+      - source: ../image_data/autoinstall.yaml
+        destination: /autoinstall.yaml
+      - source: ../@FILE@
+        destination: /cdrom/casper/@FILE@
+      - source: ../image_data/subiquity-enable
+        destination: /sbin/subiquity-enable
+      - source: ../image_data/subiquity-launcher.service
+        destination: /lib/systemd/system/subiquity-launcher.service
+      - source: ../image_data/subiquity-launch
+        destination: /sbin/subiquity-launch
+      #- source: installer-data.tar.bz2
+      #  destination: /installer-data.tar.bz2
+      - source: ../image_data/no-rate-limit.conf
+        destination: /etc/systemd/journald.conf.d/no-rate-limit.conf
+      - source: ../image_data/no-compact.conf
+        destination: /etc/systemd/system/systemd-journald.service.d/no-compact.conf
+      - source: ../image_data/no-hardening.conf
+        destination: /etc/systemd/system/systemd-journald.service.d/no-hardening.conf
+      - source: ../image_data/06_quiet.cfg
+        destination: /etc/cloud/cloud.cfg.d/06_quiet.cfg
+    execute:
+      - path: /usr/bin/systemd-machine-id-setup
+      - path: /sbin/subiquity-enable
+artifacts:
+  img:
+    -
+      name: @OUTPUT@
+  manifest:
+    name: ubuntu-core-desktop-pc-amd64.manifest
+

image_data/install-sources.yaml.in

@@ -0,0 +1,11 @@
+- default: true
+  description:
+    en: Ubuntu Core Desktop.
+  id: ubuntu-core-desktop
+  locale_support: locale-only
+  name:
+    en: Ubuntu Core Desktop
+  path: @FILE@
+  type: dd-xz:file
+  size: @SIZE@
+  variant: core

image_data/no-compact.conf

@@ -0,0 +1,4 @@
+# systemd in 23.04+ uses a newer "compact" format by default which is not
+# understood by the systemd libraries from jammy used in the subiquity snap.
+[Service]
+Environment="SYSTEMD_JOURNAL_COMPACT=0"

image_data/no-hardening.conf

@@ -0,0 +1,4 @@
+# systemd in 22.04+ uses "hash table hardening" by default which is not
+# understood by the systemd libraries from focal used in the subiquity snap.
+[Service]
+Environment="SYSTEMD_JOURNAL_KEYED_HASH=0"

image_data/no-rate-limit.conf

@@ -0,0 +1,2 @@
+[Journal]
+RateLimitIntervalSec=0