mongodb: unrecognized service in Docker - mongodb

Question

I created my own Docker container that includes the latest version of ubuntu, python3.7 and mongodb.
Dockerfile
FROM ubuntu:latest
MAINTAINER Docker
# Update apt-get sources AND install MongoDB
RUN apt-get update && apt-get upgrade -y
RUN apt-get install -y software-properties-common
RUN apt install -y gnupg2
RUN gpg2 --keyserver hkp://keyserver.ubuntu.com:80 --recv-keys F3B1AA8B
# Installation:
RUN add-apt-repository ppa:deadsnakes/ppa
RUN apt-get install -y python3.7
#Mongodb
RUN apt-key adv --keyserver hkp://keyserver.ubuntu.com:80 --recv 0C49F3730359A14518585931BC711F9BA15703C6
RUN apt-add-repository 'deb [ arch=amd64,arm64 ] http://repo.mongodb.org/apt/ubuntu xenial/mongodb-org/3.4 multiverse'
RUN apt-get update
RUN apt-get install -y mongodb-org
# Create the MongoDB data directory
RUN mkdir -p /data/db
# Create the MongoDB data directory
RUN mkdir -p /data/code
RUN mongod --version
RUN mongod --dbpath /data/db --fork --logpath /data/db/log
# COPY some Code to Container
COPY dev /data/code
# Installing pip for python modules
RUN apt-get install -y python3-pip
# Install modules
WORKDIR /data/code/
RUN pip3 install -r requirements.txt
RUN service mongodb start
RUN python3 main.py
RUN python3 server.py
EXPOSE 80
# Set /bin/bash as the dockerized entry-point application
ENTRYPOINT ["/bin/bash"]
when I run the build command:
docker build -t myContainer --no-cache .
it runs successfully till to the point where mongodb should start as a service
.
.
.
Removing intermediate container 3d43e1d1cd96
---> 62f10ce67e07
Step 21/25 : RUN service mongodb start
---> Running in 42e08e7d7638
mongodb: unrecognized service
How do I start the service? I'm trying to start the service with the command: service mongodb start. Isn't that correct? And what does the line:
Removing intermediate container 3d43e1d1cd96
means?

Answer 1

Firstly, it should be service mongod start i guess. But this is not going to solve your problem.
While using Docker, your process has to be a foreground process service mongod start will go into background & your container will exit immediately.
You should use mongod foreground process as below -
CMD ["mongod"]
Put the above CMD at the end of Dockerfile to make sure your container runs mongod.
Official Dockerfile -
https://github.com/docker-library/mongo/blob/40056ae591c1caca88ffbec2a426e4da07e02d57/3.4/Dockerfile
If you want to run multiple processes, use docker ENTRYPOINT in conjunction with supervisord or use a wrapper script.
Ref - https://docs.docker.com/config/containers/multi-service_container/