Docker was idealized for running a single service at once. The principal advantage of that is the isolation: you can keep several applications isolated one from the other.
But, it is possible to run several services in a single container with the supervisor. Supervisor is a client/server system to control processes in *nix-like systems.
The following example creates a single container with two services different from each other (the code is the same) controlled by supervisor.
You can download the code at: https://github.com/t3rcio/docker-supervisor

Dockerfile

#Dockerfile
FROM python:3.9

ENV PYTHONUNBUFFERED=1

RUN apt-get update && apt-get install -y supervisor
RUN mkdir -p /var/log/supervisor

WORKDIR /code
COPY . /code
COPY supervisord.conf /etc/supervisor/conf.d/supervisord.conf
RUN mkdir logs

RUN supervisord -c /etc/supervisor/conf.d/supervisord.conf &

docker-compose.yml

#docker-compose.yml
version: "3.9"

services:
   supervisor:
      build: .
      restart: always
      command: /usr/bin/supervisord
      volumes:
         - .:/code

Put the code above in a directory, and execute:

user@user-pc:~$ docker-compose -f docker-compose.yml -up

With that, you just made the container.
To verify whether the services are running, execute:

user@user-pc:~$ tail -f out1.log
(...)
user@user-pc:~$ tail -f out2.log

That’s it :-) With this technique, you can run several services in a single container; you can, for example, have a task scheduler and a task consumer.

References

https://docs.docker.com/config/containers/multi-service_container/

https://github.com/t3rcio/docker-supervisor#:~:text=Docker%20Tutorial%20%3D%3E%20Dockerfile%20%2B%20supervisord.conf