Docker image size is coming up to 1.7 G for Ubuntu with Python packages - docker

Question

Following is my Dockerfile :-
FROM ubuntu:18.04 AS builder
RUN apt update -y
RUN apt install python3.8 -y && apt install python3-pip -y
RUN apt install build-essential automake pkg-config libtool libffi-dev libgmp-dev -y
RUN apt install libsecp256k1-dev -y
RUN apt install openjdk-8-jre -y
RUN apt install git -y
RUN apt install libkrb5-dev -y
RUN apt install vim -y
RUN mkdir /opt/app
RUN chown -R root:root /opt/app
COPY ["requirements.txt","/opt/app/requirements.txt"]
SHELL ["/bin/bash", "-c"]
WORKDIR /opt/app
RUN pip3 install -r requirements.txt && apt-get -y clean all
RUN mkdir /opt/app/
RUN chown -R root:root /opt/app/
RUN cd /opt/app/
RUN git clone -b master https://bitbucket.org/heroes/test.git
CMD ["bash","/opt/app/bin/connect.sh"]
Docker image is generating with an image file size of 1.7G. I need to have OpenJDK hence cannot use a standard python package as a base package. When I perform docker history , I can see 2 or 3 layers (installing packages above like Python3.8, OpenJDK and libsecp256k1-dev) taking up to 400MB to 500MB in size. Ubuntu as a base image takes only 64 MB however rest of size is taking by my dockerfile layers.
I believe I need to re-write the dockerfile in order to reduce the file size which I did but nothing happened concrete.
Please assist me on reducing the image less than 1 GB at least.
[Update]
Below is my updated Dockerfile:-
FROM ubuntu:18.04 AS builder
WORKDIR /opt/app
COPY requirements.txt /opt/app/aws/requirements.txt
RUN mkdir -p /opt/app/aws \
&& apt-get update -yq \
&& apt-get install -y python3.8 python3-pip openjdk-8-jre -yq && apt-get -y clean all \
&& chown -R root:root /opt/app && cd /opt/app/aws && pip3 install -r requirements.txt
FROM alpine
COPY --from=builder /opt/app /opt/app
SHELL ["/bin/bash", "-c"]
CMD ["bash","/opt/app/aws/bin/connector/connect.sh"]
Screenshot of image size:-
After removing unwanted libraries like git, etc and using the multi-stage build, the image is now approx 1.7 GB which I believe is a lot. Any suggestion to improve this?

Answer 1

You have multiple issues going on.
First, each of your RUN apt install is increasing your image size, you should have them all in the same RUN stage, and at the end of the stage, delete all cached apt files.
Second, you're installing unnecessary stuff. Why would you need vim and git for instance? Why are you installing build-essential and other build-related stuff if you're not building anything?
Third, it seems you tried to do a multi-stage build but ended up adding everything to the same image. Read up on python multi-stage builds.

Answer 2

If we consider best practices instead of multiple RUN use single RUN.
For example
RUN apt-get update -yq \
&& apt-get install -y python3-dev build-essential -yq \
&& apt-get install curl -yq \
&& pip install -r requirements.txt \
&& apt-get purge -y --auto-remove gcc python3-dev build-essential
you can use multistage builds if you don't require git in your final image you can remove in final stage
Also if possible you can use alpine version also.

Answer 3

Try disabling recommended packages of APT with --no-install-recommends, you can read more about it from here.

Answer 4

Now the image is smaller:
FROM ubuntu:18.04 AS builder
RUN apt update -y
RUN apt install python3-pip -y
RUN apt install build-essential automake pkg-config libtool libffi-dev libgmp-dev -y
RUN apt install libsecp256k1-dev -y
RUN apt install openjdk-8-jre-headless -y
RUN apt install git -y
RUN apt install libkrb5-dev -y
RUN apt install vim -y
RUN mkdir /opt/app
RUN chown -R root:root /opt/app
COPY ["requirements.txt","/opt/app/requirements.txt"]
SHELL ["/bin/bash", "-c"]
WORKDIR /opt/app
RUN pip3 install -r requirements.txt && apt-get -y clean all
RUN mkdir /opt/app/
RUN chown -R root:root /opt/app/
RUN cd /opt/app/
RUN git clone -b master https://bitbucket.org/heroes/test.git
CMD ["bash","/opt/app/bin/connect.sh"]