I am making simple image of my python Django app in Docker. But at the end of the building container it throws next warning (I am building it on Ubuntu 20.04):
WARNING: Running pip as the 'root' user can result in broken permissions and conflicting behaviour with the system package manager. It is recommended to use a virtual environment instead
Why does it throw this warning if I am installing Python requirements inside my image? I am building my image using:
sudo docker build -t my_app:1 .
Should I be worried about warning that pip throws, because I know it can break my system?
Here is my Dockerfile:
FROM python:3.8-slim-buster
WORKDIR /app
COPY requirements.txt requirements.txt
RUN pip install -r requirements.txt
COPY . .
CMD ["python", "manage.py", "runserver", "0.0.0.0:8000"]
The way your container is built doesn't add a user, so everything is done as root.
You could create a user and install to that users's home directory by doing something like this;
FROM python:3.8.3-alpine
RUN pip install --upgrade pip
RUN adduser -D myuser
USER myuser
WORKDIR /home/myuser
COPY --chown=myuser:myuser requirements.txt requirements.txt
RUN pip install --user -r requirements.txt
ENV PATH="/home/myuser/.local/bin:${PATH}"
COPY --chown=myuser:myuser . .
CMD ["python", "manage.py", "runserver", "0.0.0.0:8000"]
You can ignore this warning since you create the image for an isolated purpose and it therefore is organizationally as isolated as a virtual environment. Not technically, but that does not matter here.
It usually should not pay off to invest the time and create a virtual environment in an image or add a user as in the other answer, only to avoid the warning since you should not have any issues with this.
Just check pip -V and pip3 -V to know whether you need to pay attention not to mistakenly use pip for Python 2 when you want pip for Python 3. But that should be it, and if you install only pip for python 3, you will not have that problem anyway.
I don't like ignoring warnings, as one day you will oversee an important one.
Here is a good explanation on best docker practices with python. Search for Example with virtualenv and you'll find this:
# temp stage
FROM python:3.9-slim as builder
WORKDIR /app
ENV PYTHONDONTWRITEBYTECODE 1
ENV PYTHONUNBUFFERED 1
RUN apt-get update && \
apt-get install -y --no-install-recommends gcc
RUN python -m venv /opt/venv
ENV PATH="/opt/venv/bin:$PATH"
COPY requirements.txt .
RUN pip install -r requirements.txt
# final stage
FROM python:3.9-slim
COPY --from=builder /opt/venv /opt/venv
WORKDIR /app
ENV PATH="/opt/venv/bin:$PATH"
Works like charm. No warnings or alike. BTW they also recommend to create a non root user for security reasons.
EDIT: to get rid of all warnings you may also want to add the following entries to the builder part of your Dockerfile (applies for Debian 8.3.x):
ARG DEBIAN_FRONTEND=noninteractive
ARG DEBCONF_NOWARNINGS="yes"
RUN python -m pip install --upgrade pip && \
...