Add vLLM CPU image build workflow

.github/workflows/build-push-vllm-cpu.yml

@@ -0,0 +1,67 @@
+name: Publish vLLM CPU images
+
+on:
+  # NOTE(sd109): Since this is checking out an external
+  # it's probably safer to leave this as workflow dispatch
+  # only so that we can manually build images from specific
+  # refs rather than automatically pulling in the latest
+  # content from the remote repo.
+  workflow_dispatch:
+    inputs:
+      vllm_ref:
+        type: string
+        description: The vLLM GitHub ref (tag, branch or commit) to build.
+        required: true
+
+jobs:
+  build_push_image:
+    name: Build and push image
+    runs-on: ubuntu-latest
+    permissions:
+      contents: read
+      id-token: write         # needed for signing the images with GitHub OIDC Token
+      packages: write         # required for pushing container images
+      security-events: write  # required for pushing SARIF files
+    steps:
+      - name: Check out the vLLM repository
+        uses: actions/checkout@v4
+        with:
+          repository: vllm-project/vllm
+          ref: ${{ inputs.vllm_ref }}
+
+      - name: Login to GitHub Container Registry
+        uses: docker/login-action@v3
+        with:
+          registry: ghcr.io
+          username: ${{ github.actor }}
+          password: ${{ secrets.GITHUB_TOKEN }}
+
+      - name: Calculate metadata for image
+        id: image-meta
+        uses: docker/metadata-action@v5
+        with:
+          images: ghcr.io/stackhpc/vllm-cpu
+          # Produce the branch name or tag and the SHA as tags
+          tags: |
+            type=raw,value=${{ inputs.vllm_ref }}
+
+      - name: Build and push image x86 image
+        uses: azimuth-cloud/github-actions/docker-multiarch-build-push@master
+        with:
+          cache-key: vllm-cpu
+          file: Dockerfile.cpu
+          platforms: linux/amd64
+          push: true
+          tags: ${{ steps.image-meta.outputs.tags }}
+          labels: ${{ steps.image-meta.outputs.labels }}
+
+      # TODO: Test whether this works
+      # - name: Build and push Arm image
+      #   uses: azimuth-cloud/github-actions/docker-multiarch-build-push@master
+      #   with:
+      #     cache-key: vllm-cpu
+      #     file: Dockerfile.cpu
+      #     platforms: linux/arm64
+      #     push: true
+      #     tags: ${{ steps.image-meta.outputs.tags }}
+      #     labels: ${{ steps.image-meta.outputs.labels }}