feat: add urunc-ready OCI image for helloworld-c#89
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Signed-off-by: danbugs <danilochiarlone@gmail.com>
Signed-off-by: danbugs <danilochiarlone@gmail.com>
Signed-off-by: danbugs <danilochiarlone@gmail.com>
Signed-off-by: danbugs <danilochiarlone@gmail.com>
Signed-off-by: danbugs <danilochiarlone@gmail.com>
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Pull request overview
This PR adds a urunc-compatible OCI image packaging flow for the examples/helloworld-c Unikraft workload, enabling it to be run under Kubernetes/containerd using the urunc unikernel runtime while also syncing the host crate lockfile to the 0.9.0 version bump.
Changes:
- Added
urunc.Dockerfile,urunc.json, andURUNC.mdto package and document a minimal urunc OCI image (kernel + initrd + metadata). - Added a
just urunc-imagerecipe to build the urunc-ready image locally. - Added a
publish-urunc-helloGitHub Actions job to build and publish the image to GHCR; updatedhost/Cargo.lockfor the 0.9.0 bump.
Reviewed changes
Copilot reviewed 5 out of 6 changed files in this pull request and generated 3 comments.
Show a summary per file
| File | Description |
|---|---|
| host/Cargo.lock | Updates the lockfile entry to reflect hyperlight-unikraft-host version 0.9.0. |
| examples/helloworld-c/URUNC.md | Adds end-user documentation for building/importing/running the image with urunc + containerd. |
| examples/helloworld-c/urunc.json | Adds urunc metadata file (base64-encoded values) for runtimes that don’t propagate annotations. |
| examples/helloworld-c/urunc.Dockerfile | Adds the OCI image build (scratch image containing kernel + initrd + metadata). |
| examples/helloworld-c/Justfile | Adds urunc-image target to build the urunc image locally. |
| .github/workflows/publish-examples.yml | Adds CI job to build and publish the urunc-ready image to GHCR. |
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| - name: Install kraft-hyperlight | ||
| if: steps.kraft-cache.outputs.cache-hit != 'true' | ||
| run: | | ||
| git clone --branch hyperlight-platform --depth 1 https://github.com/danbugs/kraftkit.git /tmp/kraftkit | ||
| cd /tmp/kraftkit && go build -o /usr/local/bin/kraft-hyperlight ./cmd/kraft | ||
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| FROM scratch | ||
| COPY .unikraft/build/helloworld-hyperlight_hyperlight-x86_64 /unikernel/kernel | ||
| COPY --from=build /output.cpio /unikernel/initrd.cpio | ||
| COPY urunc.json /urunc.json |
| - `/unikernel/initrd.cpio` — CPIO archive containing `/bin/hello` (static-PIE C binary) | ||
| - `/urunc.json` — urunc annotations identifying this as a `hyperlight` + `unikraft` workload | ||
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| When urunc runs the image, it finds `hyperlight-unikraft` on the host, bind-mounts it along with `/dev/kvm` into an isolated rootfs, and exec's: |
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Linux Benchmarks
Details
| Benchmark suite | Current: 66143d4 | Previous: 05c79a7 | Ratio |
|---|---|---|---|
hello_world (median) |
20 ms |
20 ms |
1 |
pandas (median) |
90 ms |
110 ms |
0.82 |
density (per VM) |
11 MB |
11 MB |
1 |
snapshot (disk) |
656 MiB |
656 MiB |
1 |
This comment was automatically generated by workflow using github-action-benchmark.
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Windows Benchmarks
Details
| Benchmark suite | Current: 66143d4 | Previous: 05c79a7 | Ratio |
|---|---|---|---|
hello_world (median) |
343 ms |
310 ms |
1.11 |
pandas (median) |
1039 ms |
832 ms |
1.25 |
density (per VM) |
656 MB |
656 MB |
1 |
snapshot (disk) |
664 MiB |
664 MiB |
1 |
This comment was automatically generated by workflow using github-action-benchmark.
This was referenced Jun 3, 2026
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Add a urunc-compatible OCI image for the helloworld-c example, enabling hyperlight-unikraft workloads to run on Kubernetes via urunc (CNCF unikernel container runtime).
urunc treats
hyperlight-unikraftas a host-level VMM (like QEMU), with the OCI image carrying the Unikraft kernel + initrd payload. This follows the same pattern ashello-qemu-unikraftandhello-firecracker-unikraftin the urunc ecosystem.urunc.Dockerfile,urunc.json, andURUNC.mdtoexamples/helloworld-c/just urunc-imagerecipe for local buildspublish-urunc-helloCI job to publish to GHCRCargo.lockwith 0.9.0 version bumpRelated: urunc-dev/urunc#140, urunc-dev/urunc#632