Place ISO artifacts directly into the ISO tree

For MAKE_ISO=yes builds, squashfs, kernel, initrd, manifests, and sizes
are now placed directly into config/iso-dir/iso-root/casper/ during the
build rather than creating livecd.* intermediates that get linked as
for-iso.* files and then copied into casper/ by isobuild.

This stops publishing the intermediate livecd.* artifacts so that only
livecd.*.iso and livecd.*.netboot.tar.gz are published for ISO builds.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

live-build/auto/build

@@ -424,62 +424,66 @@ case $LB_INITRAMFS in
 		;;
 esac
 
-for OUTPUT in ext2 ext3 ext4 manifest manifest-remove size squashfs; do
+# For MAKE_ISO=yes builds, artifacts (squashfs, kernel, initrd, manifests) are
+# placed directly into the ISO tree by lb_binary_layered and binary hooks.
+# Only create livecd.* intermediate artifacts for non-ISO builds.
+if [ "${MAKE_ISO}" != "yes" ]; then
+	for OUTPUT in ext2 ext3 ext4 manifest manifest-remove size squashfs; do
 		[ -e "binary/$INITFS/filesystem.$OUTPUT" ] || continue
 		ln "binary/$INITFS/filesystem.$OUTPUT" "$PREFIX.$OUTPUT"
 		chmod 644 "$PREFIX.$OUTPUT"
-done
+	done
 
-# we don't need a manifest-remove for a layered-aware installer
+	# we don't need a manifest-remove for a layered-aware installer
-# here we have a list of all new-installer flavors
+	# here we have a list of all new-installer flavors
-case $PROJECT in
+	case $PROJECT in
 		ubuntu|ubuntu-budgie|lubuntu)
 			rm -f livecd.${PROJECT}-manifest-remove
 			rm -f config/manifest-minimal-remove
 			;;
-esac
+	esac
 
-if [ -e config/manifest-minimal-remove ]; then
+	if [ -e config/manifest-minimal-remove ]; then
 		cp config/manifest-minimal-remove  "$PREFIX.manifest-minimal-remove"
-fi
+	fi
 
-if [ -e "binary/$INITFS/filesystem.dir" ]; then
+	if [ -e "binary/$INITFS/filesystem.dir" ]; then
 		(cd "binary/$INITFS/filesystem.dir/" && tar -c --sort=name --xattrs *) | \
 			gzip -9 --rsyncable > "$PREFIX.rootfs.tar.gz"
 		chmod 644 "$PREFIX.rootfs.tar.gz"
-elif [ -e binary-tar.tar.gz ]; then
+	elif [ -e binary-tar.tar.gz ]; then
 		cp -a binary-tar.tar.gz "$PREFIX.rootfs.tar.gz"
-fi
+	fi
 
-# '--initramfs none' produces different manifest names.
+	# '--initramfs none' produces different manifest names.
-if [ -e "binary/$INITFS/filesystem.packages" ]; then
+	if [ -e "binary/$INITFS/filesystem.packages" ]; then
 		ln "binary/$INITFS/filesystem.packages" "$PREFIX.manifest"
 		chmod 644 "$PREFIX.manifest"
-fi
+	fi
 
-# If a .filelist is present, use it as the filelist for the image by
+	# If a .filelist is present, use it as the filelist for the image by
-# symlinking with expected name and updating permissions
+	# symlinking with expected name and updating permissions
-if [ -e "binary/$INITFS/filesystem.filelist" ]; then
+	if [ -e "binary/$INITFS/filesystem.filelist" ]; then
 		ln "binary/$INITFS/filesystem.filelist" "$PREFIX.filelist"
 		chmod 644 "$PREFIX.filelist"
-fi
+	fi
 
-if [ -e "binary/$INITFS/filesystem.packages-remove" ]; then
+	if [ -e "binary/$INITFS/filesystem.packages-remove" ]; then
 		# Not a typo, empty manifest-remove has a single LF in it. :/
 		if [ $(cat binary/$INITFS/filesystem.packages-remove | wc -c) -gt 1 ]; then
 			ln "binary/$INITFS/filesystem.packages-remove" "$PREFIX.manifest-remove"
 			chmod 644 "$PREFIX.manifest-remove"
 		fi
-fi
+	fi
 
-# Since snaps are now Ubuntu first-class citizen, so always try fetching the
+	# Since snaps are now Ubuntu first-class citizen, so always try fetching the
-# list of seeded snaps into the manifest.  In case of layered images we skip
+	# list of seeded snaps into the manifest.  In case of layered images we skip
-# this step, as we assume they're doing it on their own at some earlier stage.
+	# this step, as we assume they're doing it on their own at some earlier stage.
-if [ -z "$PASSES" ] && [ -e "$PREFIX.manifest" ]; then
+	if [ -z "$PASSES" ] && [ -e "$PREFIX.manifest" ]; then
 		./config/snap-seed-parse "chroot/" "$PREFIX.manifest"
-fi
+	fi
 
-for FLAVOUR in $LB_LINUX_FLAVOURS; do
+	for FLAVOUR in $LB_LINUX_FLAVOURS; do
 		if [ -z "$LB_LINUX_FLAVOURS" ] || [ "$LB_LINUX_FLAVOURS" = "none" ]; then
 			continue
 		fi
@@ -527,10 +531,10 @@ for FLAVOUR in $LB_LINUX_FLAVOURS; do
 			ln "binary/$INITFS/initrd.img-$KVERS" "$PREFIX.initrd-$FLAVOUR"
 			chmod 644 "$PREFIX.initrd-$FLAVOUR"
 		fi
-done
+	done
 
-NUMFLAVOURS="$(set -- $LB_LINUX_FLAVOURS; echo $#)"
+	NUMFLAVOURS="$(set -- $LB_LINUX_FLAVOURS; echo $#)"
-if [ "$NUMFLAVOURS" = 1 ] && [ "$LB_LINUX_FLAVOURS" != "none" ]; then
+	if [ "$NUMFLAVOURS" = 1 ] && [ "$LB_LINUX_FLAVOURS" != "none" ]; then
 		# only one kernel flavour
 		if [ -f "binary/$INITFS/vmlinuz" ] && ! [ -h "binary/$INITFS/vmlinuz" ]; then
 			ln "binary/$INITFS/vmlinuz" "$PREFIX.kernel"
@@ -544,9 +548,9 @@ if [ "$NUMFLAVOURS" = 1 ] && [ "$LB_LINUX_FLAVOURS" != "none" ]; then
 		else
 			ln -sf "$PREFIX.initrd-$LB_LINUX_FLAVOURS" "$PREFIX.initrd"
 		fi
-fi
+	fi
 
-case $SUBARCH in
+	case $SUBARCH in
 		raspi)
 			# copy the kernel and initrd to a predictable directory for
 			# ubuntu-image consumption.  In some cases, like in pi2/3
@@ -561,7 +565,8 @@ case $SUBARCH in
 			cp $PREFIX.initrd $UBOOT_BOOT/initrd.img || true
 			cp $PREFIX.kernel $UBOOT_BOOT/vmlinuz || true
 			;;
-esac
+	esac
+fi
 
 case $PROJECT in
     ubuntu-cpc)
@@ -569,25 +574,14 @@ case $PROJECT in
 esac
 
 if [ "${MAKE_ISO}" = "yes" ]; then
-	# Link build artifacts with "for-iso." prefix for isobuild to consume.
+	# For non-layered builds, create squashfs with cdrom.sources directly
-	# Layered builds create squashfs via lb_binary_layered (which already
+	# in casper/. Layered builds already handle this in lb_binary_layered.
-	# creates for-iso.*.squashfs files). Single-pass builds only have
-	# ${PREFIX}.squashfs, which does not contain cdrom.sources, so we
-	# create a for-iso.filesystem.squashfs that does.
 	if [ -z "$PASSES" ]; then
 		isobuild generate-sources --mountpoint=/cdrom > chroot/etc/apt/sources.list.d/cdrom.sources
-		create_squashfs chroot ${PWD}/for-iso.filesystem.squashfs
+		create_squashfs chroot ${CASPER_DIR}/filesystem.squashfs
+		rm chroot/etc/apt/sources.list.d/cdrom.sources
 	fi
-	# Link kernel and initrd files. The ${thing#${PREFIX}} expansion strips
+	isobuild extract-casper-uuids
-	# the PREFIX, so "livecd.ubuntu-server.kernel-generic" becomes
-	# "for-iso.kernel-generic".
-	for thing in ${PREFIX}.kernel-* ${PREFIX}.initrd-*; do
-		for_iso_path=for-iso${thing#${PREFIX}}
-		if [ ! -f $for_iso_path ]; then
-			ln -v $thing $for_iso_path
-		fi
-	done
-	isobuild add-live-filesystem --artifact-prefix for-iso.
 	isobuild make-bootable --project "${PROJECT}" --capproject "$(cat config/iso-ids/capproject)" \
 		${SUBARCH:+--subarch "${SUBARCH}"}
 	isobuild make-iso --volid "$(cat config/iso-ids/vol-id)" --dest ${PREFIX}.iso

live-build/functions

@@ -1456,3 +1456,17 @@ gpt_root_partition_uuid() {
 isobuild () {
     PYTHONPATH=${LIVECD_ROOTFS_ROOT}/live-build/ ${LIVECD_ROOTFS_ROOT}/live-build/isobuild --workdir config/iso-dir "$@"
 }
+
+CASPER_DIR=config/iso-dir/iso-root/casper
+
+# Install kernel+initrd into the ISO casper directory.
+# Usage: iso_install_kernel <flavor> <kernel-path> <initrd-path>
+iso_install_kernel() {
+    local flavor=$1 kernel=$2 initrd=$3
+    local kernel_name=vmlinuz
+    case $ARCH in ppc64el) kernel_name=vmlinux ;; esac
+    local prefix=""
+    case $flavor in *-hwe) prefix="hwe-" ;; esac
+    cp "$kernel" "$CASPER_DIR/${prefix}${kernel_name}"
+    cp "$initrd" "$CASPER_DIR/${prefix}initrd"
+}

live-build/isobuild

@@ -39,10 +39,9 @@
 # Generate an apt deb822 source for the pool, assuming it is mounted at the
 # passed mountpoint, and output it on stdout.
 #
-# $ isobuild --work-dir "" add-live-filesystem --artifact-prefix ""
+# $ isobuild --work-dir "" extract-casper-uuids
 #
-# Copy the relevant artifacts to the casper directory (and extract the uuids
+# Extract casper UUID files from the initrds in the casper directory.
-# from the initrds)
 #
 # $ isobuild --work-dir "" make-bootable --project "" --capitalized-project ""
 #            --subarch ""
@@ -169,14 +168,9 @@ def generate_sources(builder, mountpoint: str):
     builder.generate_sources(mountpoint)
 
 
-@click.option(
-    "--artifact-prefix",
-    type=click.Path(dir_okay=False, resolve_path=True, path_type=pathlib.Path),
-    required=True,
-)
 @subcommand
-def add_live_filesystem(builder, artifact_prefix: pathlib.Path):
+def extract_casper_uuids(builder):
-    builder.add_live_filesystem(artifact_prefix)
+    builder.extract_casper_uuids()
 
 
 @click.option(

live-build/isobuilder/builder.py

@@ -218,7 +218,7 @@ class ISOBuilder:
             )
         )
 
-    def _extract_casper_uuids(self):
+    def extract_casper_uuids(self):
         # Extract UUID files from initrd images for casper (the live boot system).
         # Each initrd contains a conf/uuid.conf with a unique identifier that
         # casper uses at boot time to locate the correct root filesystem. These
@@ -255,43 +255,6 @@ class ISOBuilder:
                 uuid_conf.rename(dot_disk.joinpath(f"casper-uuid-{suffix}"))
                 shutil.rmtree(initrddir)
 
-    def add_live_filesystem(self, artifact_prefix: pathlib.Path):
-        casper_dir = self.iso_root.joinpath("casper")
-        artifact_dir = artifact_prefix.parent
-        filename_prefix = artifact_prefix.name
-
-        def link(src: pathlib.Path, target_name: str):
-            target = casper_dir.joinpath(target_name)
-            self.logger.log(
-                f"creating link from $ISOROOT/casper/{target_name} to $src/{src.name}"
-            )
-            target.hardlink_to(src)
-
-        kernel_name = "vmlinuz"
-        if self.arch in ("ppc64el", "riscv64"):
-            kernel_name = "vmlinux"
-
-        with self.logger.logged(
-            f"linking artifacts from {casper_dir} to {artifact_dir}"
-        ):
-            for ext in "squashfs", "squashfs.gpg", "size", "manifest", "yaml":
-                for path in artifact_dir.glob(f"{filename_prefix}*.{ext}"):
-                    newname = path.name[len(filename_prefix) :]
-                    link(path, newname)
-
-            for kernel_path in artifact_dir.glob(f"{filename_prefix}kernel*"):
-                suffix = kernel_path.name[len(filename_prefix) + len("kernel") :]
-                prefix = "hwe-" if suffix.endswith("-hwe") else ""
-                link(
-                    artifact_dir.joinpath(f"{filename_prefix}kernel{suffix}"),
-                    f"{prefix}{kernel_name}",
-                )
-                link(
-                    artifact_dir.joinpath(f"{filename_prefix}initrd{suffix}"),
-                    f"{prefix}initrd",
-                )
-        self._extract_casper_uuids()
-
     def make_bootable(self, project: str, capproject: str, subarch: str):
         configurator = make_boot_configurator_for_arch(
             self.arch,

live-build/lb_binary_layered

@@ -61,7 +61,7 @@ build_layered_squashfs () {
 
 	# Building squashfs filesystem & manifest
 	local overlay_dir="overlay.${pass}"
-	base="${PWD}/livecd.${PROJECT_FULL}.${pass}"
+	base="${PWD}/${CASPER_DIR}/${pass}"
 	squashfs_f="${base}.squashfs"
 
 	# We have already treated that pass
@@ -116,32 +116,13 @@ build_layered_squashfs () {
 		create_manifest "chroot" "${squashfs_f_manifest}.full"
 
 		# Delta manifest
-		diff -NU0 ${PWD}/livecd.${PROJECT_FULL}.$(get_parent_pass $pass).manifest.full ${squashfs_f_manifest}.full|grep -v ^@ > $squashfs_f_manifest || true
+		diff -NU0 ${PWD}/${CASPER_DIR}/$(get_parent_pass $pass).manifest.full ${squashfs_f_manifest}.full|grep -v ^@ > $squashfs_f_manifest || true
 		echo "Delta manifest:"
 		cat $squashfs_f_manifest
 
 		squashfs_f_size="${base}.size"
 		du -B 1 -s "overlay.${pass}/" | cut -f1 > "${squashfs_f_size}"
 
-		# We take first live pass for "global" ISO properties (used by installers and checkers):
-		# Prepare initrd + kernel
-		# Main manifest and size files
-		prefix="livecd.$PROJECT_FULL"
-		if [ ! -e "${prefix}.manifest" ] && $(is_live_layer "$pass"); then
-			totalsize=$(cat ${squashfs_f_size})
-			curpass="$pass"
-			while :; do
-				curpass=$(get_parent_pass $curpass)
-				# We climbed up the tree to the root layer, we are done
-				[ -z "$curpass" ] && break
-
-				totalsize=$(expr $totalsize + $(cat "${PWD}/livecd.${PROJECT_FULL}.${curpass}.size"))
-			done
-			echo ${totalsize} > "${prefix}.size"
-
-			cp "${squashfs_f_manifest}.full" "${prefix}.manifest"
-		fi
-
 		if [ -n "$lowerdirs" ]; then
 			# Although the current chroot was created as an overlay over
 			# the previous layer, many operations can result in redundant
@@ -183,23 +164,17 @@ build_layered_squashfs () {
 			${LIVECD_ROOTFS_ROOT}/sync-mtime chroot "$overlay_dir"
 		fi
 
-		create_squashfs "${overlay_dir}" ${squashfs_f}
+		# For the root layer when building with a pool, include
-		# Create a "for-iso" variant of the squashfs for ISO builds. For
+		# cdrom.sources so casper can access the ISO's package repository.
-		# the root layer (the base system) when building with a pool, we
-		# need to include cdrom.sources so casper can access the ISO's
-		# package repository. This requires regenerating the squashfs with
-		# that file included, then removing it (so it doesn't pollute the
-		# regular squashfs). Non-root layers (desktop environment, etc.)
-		# and builds without pools can just hardlink to the regular squashfs.
 		if [ -n "${POOL_SEED_NAME}" ] && $(is_root_layer $pass); then
 			isobuild generate-sources --mountpoint=/cdrom > ${overlay_dir}/etc/apt/sources.list.d/cdrom.sources
-			create_squashfs "${overlay_dir}" ${PWD}/for-iso.${pass}.squashfs
-			rm ${overlay_dir}/etc/apt/sources.list.d/cdrom.sources
 		fi
+		create_squashfs "${overlay_dir}" ${squashfs_f}
+		rm -f ${overlay_dir}/etc/apt/sources.list.d/cdrom.sources
 
 		if [ -f config/$pass.catalog-in.yaml ]; then
 			echo "Expanding catalog entry template for $pass"
-			usc_opts="--output livecd.${PROJECT_FULL}.install-sources.yaml \
+			usc_opts="--output ${CASPER_DIR}/install-sources.yaml \
 				--template config/$pass.catalog-in.yaml \
 				--size $(du -B 1 -s chroot/ | cut -f1) --squashfs ${pass}.squashfs \
 				--translations config/catalog-translations"
@@ -225,25 +200,11 @@ do
 	build_layered_squashfs "${_PASS}" ${*}
 done
 
-if [ -n "$DEFAULT_KERNEL" -a -f livecd.${PROJECT_FULL}.install-sources.yaml ]; then
+if [ -n "$DEFAULT_KERNEL" -a -f ${CASPER_DIR}/install-sources.yaml ]; then
 	write_kernel_yaml "$DEFAULT_KERNEL" "$BRIDGE_KERNEL_REASONS"
 	${LIVECD_ROOTFS_ROOT}/update-source-catalog merge \
-		--output livecd.${PROJECT_FULL}.install-sources.yaml \
+		--output ${CASPER_DIR}/install-sources.yaml \
 		--template config/kernel.yaml
 fi
 
-# Ubiquity-compatible removal manifest for ISO not using a layered-aware installer
+chmod 644 ${CASPER_DIR}/*.squashfs ${CASPER_DIR}/*.manifest* ${CASPER_DIR}/*.size
-if [ -n "$(ls livecd.${PROJECT_FULL}.*install.live.manifest.full 2>/dev/null)" ] && \
-   [ -n "$(ls livecd.${PROJECT_FULL}.*install.manifest.full 2>/dev/null)" ]; then
-	echo "$(diff livecd.${PROJECT_FULL}.*install.live.manifest.full livecd.${PROJECT_FULL}.*install.manifest.full | awk '/^< / { print $2 }')" > livecd.${PROJECT_FULL}-manifest-remove
-fi
-
-chmod 644 *.squashfs *.manifest* *.size
-
-prefix=livecd.${PROJECT_FULL}
-for artifact in ${prefix}.*; do
-	for_iso_path=for-iso${artifact#${prefix}}
-	if [ ! -f $for_iso_path ]; then
-		ln -v $artifact $for_iso_path
-	fi
-done

live-build/ubuntu-mini-iso/hooks/01-mini-iso.binary

@@ -1,8 +1,6 @@
 #!/bin/sh
 
-# Create kernel/initrd artifacts for isobuilder to consume.
+# Install kernel/initrd directly into the ISO casper directory.
-# The standard MAKE_ISO flow in auto/build expects files named
-# ${PREFIX}.kernel-${flavour} and ${PREFIX}.initrd-${flavour}.
 
 set -eu
 
@@ -14,7 +12,4 @@ case $ARCH in
         ;;
 esac
 
-PREFIX="livecd.${PROJECT}"
+iso_install_kernel generic chroot/boot/vmlinuz chroot/boot/initrd.img
-
-cp chroot/boot/vmlinuz "${PREFIX}.kernel-generic"
-cp chroot/boot/initrd.img "${PREFIX}.initrd-generic"

live-build/ubuntu-server/hooks/04-kernel-bits.binary

@@ -13,9 +13,5 @@ case $PASS in
         ;;
 esac
 
-PROJECT=$PROJECT${SUBARCH:+-$SUBARCH}
+# Install kernel and initrd directly into the ISO casper directory
-
+iso_install_kernel "$flavor" chroot/boot/vmlinu?-* chroot/boot/initrd.img-*
-# Fish out generated kernel image and initrd
-mv chroot/boot/initrd.img-* ${PWD}/livecd.${PROJECT}.initrd-$flavor
-mv chroot/boot/vmlinu?-* ${PWD}/livecd.${PROJECT}.kernel-$flavor
-chmod a+r ${PWD}/livecd.${PROJECT}.initrd-$flavor ${PWD}/livecd.${PROJECT}.kernel-$flavor

live-build/ubuntu-server/hooks/05-netboot-tarball.binary

@@ -29,8 +29,14 @@ flavor=${flavor##*.}
 
 PROJECT=$PROJECT${SUBARCH:+-$SUBARCH}
 
-KERNEL=${PWD}/livecd.${PROJECT}.kernel-$flavor
+# Read kernel/initrd from the ISO casper directory where iso_install_kernel
-INITRD=${PWD}/livecd.${PROJECT}.initrd-$flavor
+# placed them.
+kernel_name=vmlinuz
+case $ARCH in ppc64el) kernel_name=vmlinux ;; esac
+casper_prefix=""
+case $flavor in *-hwe) casper_prefix="hwe-" ;; esac
+KERNEL=${CASPER_DIR}/${casper_prefix}${kernel_name}
+INITRD=${CASPER_DIR}/${casper_prefix}initrd
 
 mkdir -p tarball/$ARCH