feat: bake podman/uidmap/fuse-overlayfs into the actions-runner image

.github/workflows/publish-podman-runner.yml

@@ -0,0 +1,58 @@
+name: Publish podman-enabled actions-runner image
+
+# PromptExecution fork addition: builds images/Dockerfile (upstream actions/runner
+# image + podman/uidmap/fuse-overlayfs baked in) and pushes it to this fork's own
+# GHCR namespace. Not the upstream release-branch-driven docker-publish.yml --
+# this just tracks main directly on our own image tag.
+
+on:
+  push:
+    branches: [main]
+    paths:
+      - images/Dockerfile
+      - .github/workflows/publish-podman-runner.yml
+  workflow_dispatch:
+    inputs:
+      runner_version:
+        description: "actions/runner release version to bundle (no leading v)"
+        required: true
+        default: "2.336.0"
+
+jobs:
+  publish-image:
+    runs-on: ubuntu-latest
+    permissions:
+      contents: read
+      packages: write
+    env:
+      REGISTRY: ghcr.io
+      IMAGE_NAME: ${{ github.repository_owner }}/actions-runner-podman
+      RUNNER_VERSION: ${{ github.event.inputs.runner_version || '2.336.0' }}
+    steps:
+      - name: Checkout repository
+        uses: actions/checkout@v4
+
+      - name: Setup Docker buildx
+        uses: docker/setup-buildx-action@v3
+
+      - name: Log into registry ${{ env.REGISTRY }}
+        uses: docker/login-action@v3
+        with:
+          registry: ${{ env.REGISTRY }}
+          username: ${{ github.actor }}
+          password: ${{ secrets.GITHUB_TOKEN }}
+
+      - name: Build and push image
+        uses: docker/build-push-action@v6
+        with:
+          context: ./images
+          platforms: linux/amd64
+          tags: |
+            ${{ env.REGISTRY }}/${{ env.IMAGE_NAME }}:latest
+            ${{ env.REGISTRY }}/${{ env.IMAGE_NAME }}:runner-${{ env.RUNNER_VERSION }}
+          build-args: |
+            RUNNER_VERSION=${{ env.RUNNER_VERSION }}
+          push: true
+          labels: |
+            org.opencontainers.image.source=${{ github.server_url }}/${{ github.repository }}
+            org.opencontainers.image.description=actions/runner ${{ env.RUNNER_VERSION }} with podman/uidmap/fuse-overlayfs baked in for rootless self-hosted podman-based CI

images/Dockerfile

@@ -54,6 +54,15 @@ RUN add-apt-repository ppa:git-core/ppa \
     && apt install -y git \
     && rm -rf /var/lib/apt/lists/*
 
+# PromptExecution fork addition: bake in podman so CI jobs on this runner
+# don't need to self-install it per-run. Ubuntu 24.04 (noble) ships podman
+# in the default repos, no PPA needed (unlike git above). uidmap/fuse-overlayfs
+# are needed for rootless podman's user-namespace + storage-driver fallback,
+# since this runs as non-root "runner" inside an already-rootless podman pod.
+RUN apt update -y \
+    && apt install -y --no-install-recommends podman uidmap fuse-overlayfs \
+    && rm -rf /var/lib/apt/lists/*
+
 RUN adduser --disabled-password --gecos "" --uid 1001 runner \
     && groupadd docker --gid 123 \
     && usermod -aG sudo runner \