ephemeral: Implement cloud-init ConfigDrive support

Implement cloud-init support for ephemeral VMs using the ConfigDrive
datasource approach, using a VFAT filesystem (more compatible than ISOs).

This uses the same approach as systemd for populating VFAT filesystems:
mkfs.vfat to create the filesystem, and mcopy (from mtools) to populate
it. We avoid using systemd-repart itself as it creates GPT-partitioned
disks rather than raw VFAT filesystems.

The ConfigDrive is attached as a raw disk image and will be
automatically detected by cloud-init in the guest VM.

Fixes: #108

Assisted-by: Claude Code (Sonnet 4.5)
Signed-off-by: Colin Walters <walters@verbum.org>

Author: cgwalters

.github/workflows/main.yml

@@ -42,9 +42,6 @@ jobs:
       - name: Run unit tests
         run: just unit
 
-      - name: Pull test images
-        run: just pull-test-images
-
       - name: Create nextest archive
         run: |
           cargo nextest archive --release -p integration-tests --archive-file nextest-archive.tar.zst
@@ -95,17 +92,12 @@ jobs:
         with:
           libvirt: 'true'
 
-      - name: Extract image lists from Justfile
-        run: |
-          echo "PRIMARY_IMAGE=$(just --evaluate PRIMARY_IMAGE)" >> $GITHUB_ENV
-          echo "ALL_BASE_IMAGES=$(just --evaluate ALL_BASE_IMAGES)" >> $GITHUB_ENV
+      - name: Install additional dependencies
+        run: sudo apt install -y go-md2man dosfstools mtools
 
       - name: Setup Rust
         uses: ./.github/actions/setup-rust
 
-      - name: Pull test images
-        run: just pull-test-images
-
       - name: Download nextest archive
         uses: actions/download-artifact@v4
         with:
@@ -121,17 +113,7 @@ jobs:
         run: chmod +x target/release/bcvk
 
       - name: Run integration tests (partition ${{ matrix.partition }}/4)
-        run: |
-          # Clean up any leftover containers before starting
-          cargo run --release --bin test-cleanup -p integration-tests 2>/dev/null || true
-
-          # Run the partitioned tests
-          cargo nextest run --archive-file nextest-archive.tar.zst \
-            --profile integration \
-            --partition hash:${{ matrix.partition }}/4
-
-          # Clean up containers after tests complete
-          cargo run --release --bin test-cleanup -p integration-tests 2>/dev/null || true
+        run: just test-integration-partition nextest-archive.tar.zst  ${{ matrix.partition }}
         env:
           BCVK_PATH: ${{ github.workspace }}/target/release/bcvk
           BCVK_PRIMARY_IMAGE: ${{ env.PRIMARY_IMAGE }}

Justfile

@@ -22,8 +22,16 @@ unit *ARGS:
 pull-test-images:
     podman pull -q {{ALL_BASE_IMAGES}} >/dev/null
 
+# Build cloud-init test image
+build-cloud-init-image:
+    #!/usr/bin/env bash
+    set -euo pipefail
+    echo "Building cloud-init test image..."
+    podman build -t localhost/bootc-cloud-init tests/fixtures/cloud-init/
+    echo "✓ Cloud-init test image built: localhost/bootc-cloud-init"
+
 # Run integration tests (auto-detects nextest, with cleanup)
-test-integration *ARGS: build pull-test-images
+test-integration *ARGS: build pull-test-images build-cloud-init-image
     #!/usr/bin/env bash
     set -euo pipefail
     export BCVK_PATH=$(pwd)/target/release/bcvk
@@ -48,6 +56,25 @@ test-integration *ARGS: build pull-test-images
 
     exit $TEST_EXIT_CODE
 
+# Run integration tests from a partition (used by CI)
+test-integration-partition ARCHIVE PARTITION: pull-test-images build-cloud-init-image
+    #!/usr/bin/env bash
+    set -euo pipefail
+
+    # Clean up any leftover containers before starting
+    cargo run --release --bin test-cleanup -p integration-tests 2>/dev/null || true
+
+    # Run the partitioned tests
+    cargo nextest run --archive-file {{ARCHIVE}} \
+      --profile integration \
+      --partition hash:{{ PARTITION }}/4
+    TEST_EXIT_CODE=$?
+
+    # Clean up containers after tests complete
+    cargo run --release --bin test-cleanup -p integration-tests 2>/dev/null || true
+
+    exit $TEST_EXIT_CODE
+
 # Clean up integration test containers
 test-cleanup:
     cargo run --release --bin test-cleanup -p integration-tests

README.md

@@ -7,6 +7,34 @@ disk images that can be imported into other virtualization frameworks.
 
 See [docs/src/installation.md](./docs/src/installation.md).
 
+## Dependencies
+
+bcvk requires the following runtime dependencies:
+
+### Core virtualization
+- **QEMU** - The core virtualization engine
+- **virtiofsd** - VirtIO filesystem daemon for sharing directories with VMs
+- **podman** - Container runtime for managing bootc images
+
+### For libvirt integration
+- **libvirt** - Virtualization management for persistent VMs
+
+### For cloud-init support
+- **dosfstools** - Provides `mkfs.vfat` for creating VFAT filesystems
+- **mtools** - Provides `mcopy` for populating VFAT images (used for cloud-init ConfigDrive)
+
+### Package installation
+
+**Debian/Ubuntu:**
+```bash
+sudo apt install qemu-kvm qemu-system qemu-utils virtiofsd podman libvirt-daemon libvirt-clients dosfstools mtools
+```
+
+**Fedora/RHEL:**
+```bash
+sudo dnf install qemu-kvm qemu-img virtiofsd podman libvirt libvirt-client dosfstools mtools
+```
+
 ## Quick Start
 
 ### Running a bootc container as ephemeral VM 

crates/integration-tests/src/main.rs

@@ -16,6 +16,7 @@ pub(crate) use integration_tests::{
 };
 
 mod tests {
+    pub mod cloud_init;
     pub mod libvirt_base_disks;
     pub mod libvirt_port_forward;
     pub mod libvirt_upload_disk;