install: Preserve /var when installing to existing root

.packit.yaml

@@ -102,6 +102,28 @@ jobs:
             context:
               running_env: "packit"
 
+  # Run package-mode migration coverage on a single guest alongside the main
+  # tier-1 integration plan.
+  - job: tests
+    trigger: pull_request
+    identifier: package-mode-tier-1
+    require:
+      label:
+        present:
+          - ci/tier-1
+    targets:
+      - centos-stream-10-x86_64
+      - centos-stream-10-aarch64
+      - fedora-latest-stable-x86_64
+      - fedora-latest-stable-aarch64
+    tmt_plan: /tmt/plans/package-mode
+    tf_extra_params:
+      environments:
+        - tmt:
+            context:
+              running_env: "packit"
+              package_source: "artifacts"
+
   # ci/merge: full target set
   - job: tests
     trigger: pull_request
@@ -124,6 +146,28 @@ jobs:
             context:
               running_env: "packit"
 
+  - job: tests
+    trigger: pull_request
+    identifier: package-mode-full
+    require:
+      label:
+        present:
+          - ci/merge
+    targets:
+      - centos-stream-9-x86_64
+      - centos-stream-9-aarch64
+      - centos-stream-10-x86_64
+      - centos-stream-10-aarch64
+      - fedora-all-x86_64
+      - fedora-all-aarch64
+    tmt_plan: /tmt/plans/package-mode
+    tf_extra_params:
+      environments:
+        - tmt:
+            context:
+              running_env: "packit"
+              package_source: "artifacts"
+
   - job: propose_downstream
     trigger: release
     dist_git_branches:

Justfile

@@ -205,6 +205,33 @@ build-ukiboot-update-test-image: build-ukiboot-test-image
 test-ukiboot: build-ukiboot-update-test-image
     cargo xtask run-tmt --env=BOOTC_variant=composefs --filesystem=ext4 --boot-type=aboot --seal-state=unsealed --upgrade-image={{ukiboot_img}}:v2 {{ukiboot_img}}:v1 aboot
 
+# Run the package-mode migration plan against the current checkout image.
+# The VM cannot share controller Podman storage, so transfer it as an OCI archive.
+[group('testing')]
+test-tmt-package-mode:
+    #!/bin/bash
+    set -euo pipefail
+    just build
+    archive_dir=$(mktemp -d -- tmt/plans/.package-mode-local.XXXXXX)
+    cleanup() {
+        rm -rf -- "$archive_dir"
+    }
+    trap cleanup EXIT
+    trap 'cleanup; exit 130' INT
+    trap 'cleanup; exit 143' TERM
+    archive_path="$archive_dir/bootc.oci"
+    if [[ -e "$archive_path" ]]; then
+        echo "Refusing to overwrite existing archive: $archive_path" >&2
+        exit 1
+    fi
+    podman save --format oci-archive --output "$archive_path" localhost/bootc
+    tmt \
+        --context=running_env=packit \
+        --context=package_source=local \
+        --context="test_disk_image=${test_disk_image:-centos-stream-10}" \
+        run --environment "PACKAGE_MODE_IMAGE_ARCHIVE=$archive_path" \
+        plans --name '^/tmt/plans/package-mode$'
+
 # Split out from `test-container` because, unlike the container integration tests,
 # unit tests don't depend on variant/filesystem/bootloader/boot_type/seal_state, so
 # CI runs this once per OS (in the `package` job) instead of once per test-integration

crates/lib/src/cli.rs

@@ -348,6 +348,9 @@ pub(crate) enum InstallOpts {
     /// the running host root filesystem. Currently, the host root filesystem's `/boot` partition
     /// will be wiped, but the content of the existing root will otherwise be retained, and will
     /// need to be cleaned up if desired when rebooted into the new root.
+    ///
+    /// When migrating from a package-mode system, use `--preserve-var` to copy `/var` data
+    /// into the new deployment before rebooting.
     ToExistingRoot(crate::install::InstallToExistingRootOpts),
     /// Nondestructively create a fresh installation state inside an existing bootc system.
     ///
@@ -2400,10 +2403,14 @@ async fn run_from_opt(opt: Opt) -> Result<CliExitStatus> {
             InstallOpts::Mount(opts) => crate::mount::mount(opts).await,
             #[cfg(feature = "install-to-disk")]
             InstallOpts::ToDisk(opts) => crate::install::install_to_disk(opts).await,
-            InstallOpts::ToFilesystem(opts) => {
-                crate::install::install_to_filesystem(opts, false, crate::install::Cleanup::Skip)
-                    .await
-            }
+            InstallOpts::ToFilesystem(opts) => crate::install::install_to_filesystem(
+                opts,
+                false,
+                crate::install::Cleanup::Skip,
+                false,
+            )
+            .await
+            .map(|_| ()),
             InstallOpts::ToExistingRoot(opts) => {
                 crate::install::install_to_existing_root(opts).await
             }