fix: add missing UCX/NIXL native libraries to sglang runtime (#6939)

Signed-off-by: Anant Sharma <anants@nvidia.com>

container/templates/sglang_runtime.Dockerfile

@@ -18,6 +18,7 @@ RUN apt remove -y python3-apt python3-blinker && \
 
 # This ARG is still utilized for SGLANG Version extraction
 ARG RUNTIME_IMAGE_TAG
+ARG ARCH_ALT
 WORKDIR /workspace
 
 # Install NATS and ETCD
@@ -65,6 +66,25 @@ COPY --chmod=775 --chown=dynamo:0 --from=wheel_builder /opt/dynamo/dist/*.whl /o
 COPY --chmod=775 --chown=dynamo:0 --from=wheel_builder /opt/dynamo/dist/nixl/ /opt/dynamo/wheelhouse/nixl/
 COPY --chmod=775 --chown=dynamo:0 --from=wheel_builder /workspace/nixl/build/src/bindings/python/nixl-meta/nixl-*.whl /opt/dynamo/wheelhouse/nixl/
 
+# NIXL environment and native libraries
+ENV NIXL_PREFIX=/opt/nvidia/nvda_nixl
+ENV NIXL_LIB_DIR=$NIXL_PREFIX/lib/${ARCH_ALT}-linux-gnu
+ENV NIXL_PLUGIN_DIR=$NIXL_LIB_DIR/plugins
+
+# Copy UCX and NIXL native libraries to system directories
+COPY --from=wheel_builder /usr/local/ucx /usr/local/ucx
+COPY --chown=dynamo:0 --from=wheel_builder $NIXL_PREFIX $NIXL_PREFIX
+COPY --chown=dynamo:0 --from=wheel_builder /opt/nvidia/nvda_nixl/lib64/. ${NIXL_LIB_DIR}/
+
+ENV PATH=/usr/local/ucx/bin:$PATH
+
+ENV LD_LIBRARY_PATH=\
+$NIXL_LIB_DIR:\
+$NIXL_PLUGIN_DIR:\
+/usr/local/ucx/lib:\
+/usr/local/ucx/lib/ucx:\
+$LD_LIBRARY_PATH
+
 ENV SGLANG_VERSION="${RUNTIME_IMAGE_TAG%%-*}"
 
 {% if target not in ("dev", "local-dev") %}