diff --git a/Dockerfile b/Dockerfile
index 919c77c98..16a7cc22f 100644
--- a/Dockerfile
+++ b/Dockerfile
@@ -5,24 +5,26 @@ FROM nvidia/cuda:12.9.0-devel-ubuntu24.04 AS sage-builder
 
 ENV DEBIAN_FRONTEND=noninteractive \
     PIP_DISABLE_PIP_VERSION_CHECK=1 \
-    PIP_NO_CACHE_DIR=1
+    PIP_NO_CACHE_DIR=1 \
+    VENV=/opt/venv
 
-# Python 3.12 and build tools (Ubuntu 24.04 ships Python 3.12)
+# Python 3.12 and build tools
 RUN apt-get update && apt-get install -y --no-install-recommends \
     python3 python3-pip python3-venv \
     git build-essential cmake \
  && rm -rf /var/lib/apt/lists/*
 
-# Make 'python' point to Python 3
-RUN update-alternatives --install /usr/bin/python python /usr/bin/python3 1
+# Create a venv to avoid PEP 668 'externally-managed-environment'
+RUN python3 -m venv "$VENV"
+ENV PATH="$VENV/bin:$PATH"
 
 WORKDIR /tmp/sage
 
-# Match runtime Torch (cu129) before building the extension so ABIs align
+# Install Torch (cu129) in the venv before building the extension so ABIs align
 RUN python -m pip install --upgrade pip setuptools wheel \
  && python -m pip install torch torchvision torchaudio --extra-index-url https://download.pytorch.org/whl/cu129
 
-# Shallow clone latest SageAttention and build a cp312 wheel
+# Shallow clone latest SageAttention and build a cp312 wheel from source
 RUN git clone --depth 1 https://github.com/thu-ml/SageAttention.git . \
  && python -m pip wheel . --no-deps --no-build-isolation -w /dist
 
@@ -31,7 +33,6 @@ RUN git clone --depth 1 https://github.com/thu-ml/SageAttention.git . \
 # --------------------------
 FROM python:3.12.11-slim-trixie
 
-# Environment
 ENV DEBIAN_FRONTEND=noninteractive \
     PYTHONUNBUFFERED=1 \
     COMFY_AUTO_INSTALL=1 \
@@ -40,34 +41,25 @@ ENV DEBIAN_FRONTEND=noninteractive \
 
 # System deps
 RUN apt-get update && apt-get install -y --no-install-recommends \
-    git \
-    build-essential \
-    cmake \
-    libgl1 \
-    libglx-mesa0 \
-    libglib2.0-0 \
-    fonts-dejavu-core \
-    fontconfig \
-    util-linux \
+    git build-essential cmake \
+    libgl1 libglx-mesa0 libglib2.0-0 \
+    fonts-dejavu-core fontconfig util-linux \
  && rm -rf /var/lib/apt/lists/*
 
 # Create runtime user/group
 RUN groupadd --gid 1000 appuser \
  && useradd --uid 1000 --gid 1000 --create-home --shell /bin/bash appuser
 
-# Workdir
 WORKDIR /app/ComfyUI
 
-# Leverage layer caching: install deps before copying full tree
+# Install core deps
 COPY requirements.txt ./
-
-# Core Python deps (Torch CUDA 12.9, ComfyUI reqs), media/NVML libs
 RUN python -m pip install --upgrade pip setuptools wheel \
  && python -m pip install torch torchvision torchaudio --extra-index-url https://download.pytorch.org/whl/cu129 \
  && python -m pip install -r requirements.txt \
  && python -m pip install imageio-ffmpeg "av>=14.2" nvidia-ml-py
 
-# Bring in the SageAttention 2.2 wheel compiled in the builder stage and install it
+# Install the SageAttention wheel built in the builder stage
 COPY --from=sage-builder /dist/sageattention-*.whl /tmp/
 RUN python -m pip install /tmp/sageattention-*.whl
 
@@ -80,8 +72,6 @@ RUN chmod +x /entrypoint.sh \
  && chown -R appuser:appuser /app /home/appuser /entrypoint.sh
 
 EXPOSE 8188
-
-# Start as root so entrypoint can adjust ownership and drop privileges
 USER root
 ENTRYPOINT ["/entrypoint.sh"]
 CMD ["python", "main.py", "--listen", "0.0.0.0", "--use-sage-attention"]