osbuild: use bootc install to deploy the container

build.sh

@@ -208,7 +208,8 @@ patch_osbuild() {
         /usr/lib/coreos-assembler/0002-osbuild-util-containers.py-rename-variable.patch           \
         /usr/lib/coreos-assembler/0003-osbuild-util-containers.py-drop-copy-when-using-cont.patch \
         /usr/lib/coreos-assembler/0004-drop-remove_signatures-from-org.osbuild.container-de.patch \
-        /usr/lib/coreos-assembler/0005-tools-osbuild-mpp-support-mpp-resolve-for-org.osbuil.patch |
+        /usr/lib/coreos-assembler/0005-tools-osbuild-mpp-support-mpp-resolve-for-org.osbuil.patch \
+        /usr/lib/coreos-assembler/0001-stages-add-new-link-stage.patch |
             patch -d /usr/lib/osbuild -p1
 
     # And then move the files back; supermin appliance creation will need it back

src/0001-stages-add-new-link-stage.patch

@@ -0,0 +1,132 @@
+From f53b6e1c5a8f0c26ee4f92641274a8cdba4b1d5a Mon Sep 17 00:00:00 2001
+From: jbtrystram <[email protected]>
+Date: Tue, 21 Oct 2025 13:13:57 +0200
+Subject: [PATCH 1/2] stages: add new link stage
+
+This introduces a new stage, `org.osbuild.ln`, for creating
+links within the filesystem tree.
+
+This takes a list of paths, each with a `target` and a `link_name`
+parameters, inspired by the copy stage.
+
+The target is a simple string because we want the link to be either
+absolute or relative.
+---
+ stages/org.osbuild.ln           | 31 ++++++++++++++++
+ stages/org.osbuild.ln.meta.json | 66 +++++++++++++++++++++++++++++++++
+ 2 files changed, 97 insertions(+)
+ create mode 100755 stages/org.osbuild.ln
+ create mode 100644 stages/org.osbuild.ln.meta.json
+
+diff --git a/stages/org.osbuild.ln b/stages/org.osbuild.ln
+new file mode 100755
+index 00000000..8268685d
+--- /dev/null
++++ b/stages/org.osbuild.ln
+@@ -0,0 +1,31 @@
++#!/usr/bin/python3
++import os
++import sys
++
++import osbuild.api
++from osbuild.util import parsing
++
++
++def main(args, options):
++    items = options["paths"]
++
++    for path in items:
++        target = path["target"]
++        link_name = parsing.parse_location(path["link_name"], args)
++        symbolic = path.get("symbolic", False)
++
++        print(f"Linking '{link_name}' -> '{target}'")
++        if symbolic:
++            print(f"Creating symbolic link: '{link_name}' -> '{target}'")
++            os.symlink(target, link_name)
++        else:
++            print(f"Creating hard link: '{link_name}' -> '{target}'")
++            os.link(target, link_name)
++
++    return 0
++
++
++if __name__ == '__main__':
++    _args = osbuild.api.arguments()
++    r = main(_args, _args["options"])
++    sys.exit(r)
+diff --git a/stages/org.osbuild.ln.meta.json b/stages/org.osbuild.ln.meta.json
+new file mode 100644
+index 00000000..81f297be
+--- /dev/null
++++ b/stages/org.osbuild.ln.meta.json
+@@ -0,0 +1,66 @@
++{
++  "summary": "Create links",
++  "description": [
++    "Creates links within the tree or mounts. The target and link_name are specified as URLs.",
++    "Only allows tree or mounts URLs."
++  ],
++  "schema_2": {
++    "options": {
++      "additionalProperties": false,
++      "required": [
++        "paths"
++      ],
++      "properties": {
++        "paths": {
++          "description": "Array of links to create.",
++          "type": "array",
++          "minItems": 1,
++          "items": {
++            "type": "object",
++            "additionalProperties": false,
++            "required": [
++              "target",
++              "link_name"
++            ],
++            "properties": {
++              "target": {
++                "type": "string",
++                "description": "The target for the link, relative or absolute"
++              },
++              "link_name": {
++                "oneOf": [
++                  {
++                    "type": "string",
++                    "description": "The link path, if in a mount",
++                    "pattern": "^mount://[^/]+/"
++                  },
++                  {
++                    "type": "string",
++                    "description": "The link path, if in a tree",
++                    "pattern": "^tree://"
++                  }
++                ]
++              },
++              "symbolic": {
++                "type": "boolean",
++                "description": "Use a symbolic link instead of hard-linking. Defaults to False.",
++                "default": false
++              }
++            }
++          }
++        }
++      }
++    },
++    "devices": {
++      "type": "object",
++      "additionalProperties": true
++    },
++    "mounts": {
++      "type": "array"
++    },
++    "inputs": {
++      "type": "object",
++      "additionalProperties": true
++    }
++  }
++}
+-- 
+2.51.0
+

src/cmd-osbuild

@@ -408,10 +408,23 @@ main() {
     else
         cmd="runvm_with_cache"
     fi
-    $cmd -- /usr/lib/coreos-assembler/runvm-osbuild                                                     \
-                --config "${runvm_osbuild_config_json}"                                                 \
-                --mpp "/usr/lib/coreos-assembler/osbuild-manifests/coreos.osbuild.${basearch}.mpp.yaml" \
-                --outdir "${outdir}"                                                                    \
+
+    # Use the bootc install to-filesystem manifest if applicable
+    bootc_suffix=""
+    if should_use_bootc_install; then
+        bootc_suffix=".bootc"
+    fi
+
+    manifest_path="/usr/lib/coreos-assembler/osbuild-manifests/coreos.osbuild.${basearch}${bootc_suffix}.mpp.yaml"
+
+    # To get a shell in the osbuild supermin VM uncomment this.
+    # osbuild can then be started with `bash tmp/build.<artifact>/cmd.sh`
+    # See comment about checkpoints in runvm-osbuild
+    # RUNVM_SHELL=1 \
+    $cmd -- /usr/lib/coreos-assembler/runvm-osbuild                                                                          \
+                --config "${runvm_osbuild_config_json}"                                                                      \
+                --mpp "${manifest_path}"                                                                                     \
+                --outdir "${outdir}"                                                                                         \
                 --platforms "$(IFS=,; echo "${platforms[*]}")"
 
     for platform in "${platforms[@]}"; do

src/cmdlib.sh

@@ -148,28 +148,53 @@ yaml2json() {
     python3 -c 'import sys, json, yaml; json.dump(yaml.safe_load(sys.stdin), sys.stdout, sort_keys=True)' < "$1" > "$2"
 }
 
-should_build_with_buildah() {
-    local variant manifest
-    if [ -n "${COSA_BUILD_WITH_BUILDAH:-}" ]; then
-        if [ "${COSA_BUILD_WITH_BUILDAH:-}" = 1 ]; then
+# Common helper to check for features that can be enabled via an env var or
+# in the manifest metadata.
+_should_enable_feature() {
+    local env_var_name=$1
+    local metadata_key=$2
+    local env_var_value
+    # Indirect expansion
+    env_var_value=${!env_var_name:-}
+
+    if [ -n "${env_var_value}" ]; then
+        if [ "${env_var_value}" = 1 ]; then
             return 0
         else
             return 1
         fi
     fi
+
+    # Make sure we are in the config directory (e.g. cmd-osbuild set a different working directory).
+    # When called very early (e.g. cmd-fetch), configdir isn't initialized yet so we assume we are in the top
+    # cosa initialized dir and use `src/config`.
+    # We redirect the output to /dev/null to avoid the noisy `dirs` output.
+    set +u
+    pushd "${configdir:-src/config}" > /dev/null
+    set -u
     # this slightly duplicates some logic in `prepare_build`, but meh...
-    if [[ -f "src/config.json" ]]; then
-        variant="$(jq --raw-output '."coreos-assembler.config-variant"' src/config.json)"
-        manifest="src/config/manifest-${variant}.yaml"
+    if [[ -f "../config.json" ]]; then
+        variant="$(jq --raw-output '."coreos-assembler.config-variant"' ../config.json)"
+        manifest="manifest-${variant}.yaml"
     else
-        manifest="src/config/manifest.yaml"
+        manifest="manifest.yaml"
     fi
-    if [ "$(yq .metadata.build_with_buildah "${manifest}")" = true ]; then
+    if [ "$(yq ".metadata.${metadata_key}" "${manifest}")" = true ]; then
+        popd > /dev/null
         return 0
     fi
+    popd > /dev/null
     return 1
 }
 
+should_use_bootc_install() {
+    _should_enable_feature "COSA_OSBUILD_USE_BOOTC_INSTALL" "use_bootc_install"
+}
+
+should_build_with_buildah() {
+    _should_enable_feature "COSA_BUILD_WITH_BUILDAH" "build_with_buildah"
+}
+
 prepare_build() {
     preflight
     preflight_kvm
@@ -759,8 +784,8 @@ runvm() {
     # include COSA in the image
     find /usr/lib/coreos-assembler/ -type f > "${vmpreparedir}/hostfiles"
     cat <<EOF >> "${vmpreparedir}/hostfiles"
-/usr/lib/osbuild/stages/org.osbuild.coreos.live-artifacts.mono
-/usr/lib/osbuild/stages/org.osbuild.coreos.live-artifacts.mono.meta.json
+/usr/lib/osbuild/stages/org.osbuild.ln
+/usr/lib/osbuild/stages/org.osbuild.ln.meta.json
 EOF
 
     # and include all GPG keys
@@ -787,7 +812,7 @@ rc=0
 if [ -z "${RUNVM_SHELL:-}" ]; then
   (cd ${workdir}; bash ${tmp_builddir}/cmd.sh |& tee /dev/virtio-ports/cosa-cmdout) || rc=\$?
 else
-  (cd ${workdir}; bash)
+  (cd ${workdir}; RUNVM_SHELL=${RUNVM_SHELL:-} bash)
 fi
 echo \$rc > ${rc_file}
 if [ -n "\${cachedev}" ]; then