feat: add pyhl container image for device plugin deployments (#109)

* feat: add pyhl container image for device plugin deployments

Signed-off-by: danbugs <danilochiarlone@gmail.com>

* ci: publish pyhl container image to GHCR

Signed-off-by: danbugs <danilochiarlone@gmail.com>

* feat: add --setup-only flag to entrypoint for init container use

Signed-off-by: danbugs <danilochiarlone@gmail.com>

* fix: use POSIX sh and add EXIT trap in entrypoint

Signed-off-by: danbugs <danilochiarlone@gmail.com>

---------

Signed-off-by: danbugs <danilochiarlone@gmail.com>

Author: danbugs

.github/workflows/publish-examples.yml

@@ -7,6 +7,7 @@ on:
     tags: ['v*']
     paths:
       - 'examples/**'
+      - 'host/**'
       - 'runtimes/**'
       - '.github/workflows/publish-examples.yml'
 
@@ -230,6 +231,37 @@ jobs:
             docker push $VERSION_TAG
           fi
 
+  # Publish a runnable pyhl container image (pyhl + kernel + initrd).
+  # Designed for the hyperlight-on-kubernetes device plugin — the pod
+  # gets /dev/kvm and pyhl handles VM lifecycle internally.
+  publish-pyhl:
+    needs: [publish-pyhl-initrd, publish-kernels]
+    runs-on: ubuntu-latest
+    permissions:
+      contents: read
+      packages: write
+    steps:
+      - uses: actions/checkout@v4
+
+      - name: Log in to GHCR
+        uses: docker/login-action@v3
+        with:
+          registry: ${{ env.REGISTRY }}
+          username: ${{ github.actor }}
+          password: ${{ secrets.GITHUB_TOKEN }}
+
+      - name: Build and push pyhl image
+        run: |
+          IMAGE=${{ env.IMAGE_BASE }}/pyhl:latest
+          docker build --platform linux/amd64 \
+            -f host/pyhl.Dockerfile -t $IMAGE .
+          docker push $IMAGE
+          if [[ "${{ github.ref_type }}" == "tag" ]]; then
+            VERSION_TAG=${{ env.IMAGE_BASE }}/pyhl:${{ github.ref_name }}
+            docker tag $IMAGE $VERSION_TAG
+            docker push $VERSION_TAG
+          fi
+
   # Publish the python-agent-driver rootfs CPIO as its own image so
   # `pyhl setup` can pull the initrd (and kernel, above) from GHCR
   # without having to build the driver image locally.

host/pyhl-entrypoint.sh

@@ -0,0 +1,17 @@
+#!/bin/sh
+set -e
+
+if [ ! -f "$PYHL_HOME/snapshot/index.json" ]; then
+    staging=$(mktemp -d)
+    trap 'rm -rf "$staging"' EXIT
+    mkdir -p "$staging/.unikraft/build"
+    ln -s "$PYHL_HOME/kernel" "$staging/.unikraft/build/driver_hyperlight-x86_64"
+    ln -s "$PYHL_HOME/initrd.cpio" "$staging/driver-initrd.cpio"
+    pyhl setup --dest "$PYHL_HOME" --from "$staging" --net --force
+fi
+
+if [ "$1" = "--setup-only" ]; then
+    exit 0
+fi
+
+exec pyhl run --dest "$PYHL_HOME" --net "$@"

host/pyhl.Dockerfile

@@ -0,0 +1,33 @@
+# pyhl container image — runs Python scripts in Hyperlight micro-VMs.
+#
+# Bundles the pyhl CLI, the python-agent-driver kernel, and its initrd
+# into a single runnable container.  Designed for the
+# hyperlight-on-kubernetes device plugin: the pod gets /dev/kvm via
+# `hyperlight.dev/hypervisor: "1"` and pyhl handles the rest.
+#
+# Build (from repo root):
+#   docker build -f host/pyhl.Dockerfile -t pyhl .
+#
+# Run:
+#   docker run --rm --device /dev/kvm pyhl /path/to/script.py
+#   echo 'print("hi")' | docker run --rm -i --device /dev/kvm pyhl -
+
+FROM rust:1.87-bookworm AS builder
+COPY host/ /src/host/
+WORKDIR /src/host
+RUN cargo build --release --bin pyhl
+
+FROM ghcr.io/hyperlight-dev/hyperlight-unikraft/python-agent-driver-kernel:latest AS kernel
+FROM ghcr.io/hyperlight-dev/hyperlight-unikraft/python-agent-driver-initrd:latest AS initrd
+
+FROM debian:bookworm-slim
+RUN apt-get update && apt-get install -y --no-install-recommends ca-certificates \
+    && rm -rf /var/lib/apt/lists/*
+COPY --from=builder /src/host/target/release/pyhl /usr/local/bin/
+COPY --from=kernel /kernel /opt/pyhl/kernel
+COPY --from=initrd /initrd.cpio /opt/pyhl/initrd.cpio
+COPY host/pyhl-entrypoint.sh /entrypoint.sh
+RUN chmod +x /entrypoint.sh && chown -R 65534:65534 /opt/pyhl
+ENV PYHL_HOME=/opt/pyhl
+USER 65534
+ENTRYPOINT ["/entrypoint.sh"]