[Doc] add visualization for multi-stage dockerfile (#4456)

Signed-off-by: Prashant Gupta <prashantgupta@us.ibm.com>
Co-authored-by: Roger Wang <ywang@roblox.com>

Dockerfile

 # The vLLM Dockerfile is used to construct vLLM image that can be directly used
 # to run the OpenAI compatible server.
 
+# Please update any changes made here to
+# docs/source/dev/dockerfile/dockerfile.rst and
+# docs/source/assets/dev/dockerfile-stages-dependency.png
+
 #################### BASE BUILD IMAGE ####################
 # prepare basic build environment
 FROM nvidia/cuda:12.1.0-devel-ubuntu22.04 AS dev

docs/source/dev/dockerfile/dockerfile.rst

+Dockerfile
+====================
+
+See `here <https://github.com/vllm-project/vllm/blob/main/Dockerfile>`_ for the main Dockerfile to construct 
+the image for running an OpenAI compatible server with vLLM.
+
+-  Below is a visual representation of the multi-stage Dockerfile. The build graph contains the following nodes:
+
+   - All build stages
+   - The default build target (highlighted in grey)
+   - External images (with dashed borders)
+   
+   The edges of the build graph represent:
+   
+   - FROM ... dependencies (with a solid line and a full arrow head)
+   - COPY --from=... dependencies (with a dashed line and an empty arrow head)
+   - RUN --mount=(.*)from=... dependencies (with a dotted line and an empty diamond arrow head)
+
+   .. figure:: ../../assets/dev/dockerfile-stages-dependency.png
+      :alt: query
+      :width: 100%
+      :align: center
+
+   Made using: https://github.com/patrickhoefler/dockerfilegraph
+
+   Commands to regenerate the build graph (make sure to run it **from the `root` directory of the vLLM repository** where the dockerfile is present):
+
+   .. code:: bash
+
+      dockerfilegraph -o png --legend --dpi 200 --max-label-length 50 --filename Dockerfile
+
+   or in case you want to run it directly with the docker image:
+   
+   .. code:: bash
+
+      docker run \
+         --rm \
+         --user "$(id -u):$(id -g)" \
+         --workdir /workspace \
+         --volume "$(pwd)":/workspace \
+         ghcr.io/patrickhoefler/dockerfilegraph:alpine \
+         --output png \
+         --dpi 200 \
+         --max-label-length 50 \
+         --filename Dockerfile \
+         --legend
+
+   (To run it for a different file, you can pass in a different argument to the flag `--filename`.)
+
+   
\ No newline at end of file

docs/source/index.rst

@@ -102,6 +102,7 @@ Documentation
    dev/sampling_params
    dev/engine/engine_index
    dev/kernel/paged_attention
+   dev/dockerfile/dockerfile
 
 Indices and tables
 ==================