By default, the official Mage docker images in DockerHub are using the root users. For production deployment, it’s recommended to use non-root users in the docker image to restrict access to the system for better security. Here is the Dockerfile template that you can use to build your custom docker image that runs Mage as non-root user. 
ARG VERSION

FROM mageai/mageai:$VERSION

# Add non-root user for Mage service
RUN adduser --disabled-password --gecos '' mage && adduser mage mage

# Grant the user permissions to the Mage related directories
RUN mkdir /home/src/mage_data; chown -R mage /home/src/mage_data
RUN mkdir /home/src/default_repo; chown -R mage /home/src/default_repo

RUN pip3 install -r path/to/requirements.txt

# Set the Mage user
USER mage

ENV PYTHONPATH="${PYTHONPATH}:/home/mage/.local/lib/python3.10/site-packages"

WORKDIR /home/src

CMD ["/bin/sh", "-c", "/app/run_app.sh"]