[Doc][Build] update after removing vllm-nccl (#5103)

Co-authored-by: Roger Wang <136131678+ywang96@users.noreply.github.com>

Dockerfile

@@ -79,12 +79,6 @@ RUN --mount=type=cache,target=/root/.cache/ccache \
 COPY .buildkite/check-wheel-size.py check-wheel-size.py
 RUN python3 check-wheel-size.py dist
 
-# the `vllm_nccl` package must be installed from source distribution
-# pip is too smart to store a wheel in the cache, and other CI jobs
-# will directly use the wheel from the cache, which is not what we want.
-# we need to remove it manually
-RUN --mount=type=cache,target=/root/.cache/pip \
-    pip cache remove vllm_nccl*
 #################### EXTENSION Build IMAGE ####################
 
 #################### vLLM installation IMAGE ####################

docs/source/serving/deploying_with_docker.rst

@@ -51,4 +51,4 @@ To run vLLM:
 
 .. note::
 
-        vLLM docker image is currently designed to be run under the root user (contribution welcomed for changing this!). It will try to load library at runtime under the root user's home directory, e.g. `/root/.config/vllm/nccl/cu12/libnccl.so.2.18.1` . If you are running the container under a different user, you may need to change the permissions of the library (and all the parent directories) to allow the user to access it. Then run vLLM with environment variable `VLLM_NCCL_SO_PATH=/root/.config/vllm/nccl/cu12/libnccl.so.2.18.1` .
+        **For `v0.4.1` and `v0.4.2` only** - the vLLM docker images under these versions are supposed to be run under the root user since a library under the root user's home directory, i.e. ``/root/.config/vllm/nccl/cu12/libnccl.so.2.18.1`` is required to be loaded during runtime. If you are running the container under a different user, you may need to first change the permissions of the library (and all the parent directories) to allow the user to access it, then run vLLM with environment variable ``VLLM_NCCL_SO_PATH=/root/.config/vllm/nccl/cu12/libnccl.so.2.18.1`` .