Launch service at container startup - mysql

Question

I've already searched for ideas for my problem but I didn't found anything that I could use.
I have a dockerfile with MySql & Apache2 and I want them start when the container start too but I can't do it in the dockerfile with CMD or ENTRYPOINT because I want to put a tail to keep my container alive and I want to be able to go in bash mode directly with run -it container bash and if I put a tail in script or CMD/ENTRYPOINT it's impossible.
I tried to launch my services with update-rc.d but it doesn't work at all...
I tried to start MySql & Apache2 with a script with ENTRYPOINT and put the tail with CMD but I think it's impossible after a lot of try with differents dockerfile and script...
Here my dockerfile:
###
# Dockerfile db MySql
###
###
# Image
###
FROM debian:jessie
###
# Volume
###
VOLUME /usr/projet/volumes/volume_db
###
# Proxy & installations
###
RUN export http_proxy="myproxy:port" \
&& export https_proxy="myproxy:port" \
&& apt-get update \
&& apt-get install -y vim \
&& echo "mysql-server mysql-server/root_password select root" | debconf-set-selections \
&& echo "mysql-server mysql-server/root_password_again select root" | debconf-set-selections \
&& apt-get install -y mysql-server \
&& apt-get install -y mysql-client \
&& service mysql start \
#&& service mysql stop \
&& echo "phpmyadmin phpmyadmin/dbconfig-install boolean true" | debconf-set-selections \
&& echo "phpmyadmin phpmyadmin/app-password-confirm password root" | debconf-set-selections \
&& echo "phpmyadmin phpmyadmin/mysql/admin-user string root" | debconf-set-selections \
&& echo "phpmyadmin phpmyadmin/mysql/admin-pass password root" | debconf-set-selections \
&& echo "phpmyadmin phpmyadmin/mysql/app-pass password root" | debconf-set-selections \
&& echo "phpmyadmin phpmyadmin/reconfigure-webserver multiselect apache2" | debconf-set-selections \
&& apt-get install -y phpmyadmin\
&& apt-get autoremove --purge
###
# Script startup
###
#COPY script_start /etc/init.d/
RUN update-rc.d apache2 defaults \
&& update-rc.d mysql defaults
###
# Variable env
###
ENV MYSQL_ROOT_PASSWORD=root
###
###
# Port exposition & cmd
###
EXPOSE 3306 80
CMD tail -F -n0 /etc/hosts
And there my script:
#!/bin/bash
### BEGIN INIT INFO
# Provides: script_start
# Required-Start: $local_fs $syslog
# Required-Stop: $local_fs $syslog
# Default-Start: 2
# Default-Stop:
# Short-Description: Boot services mysql apache2
# Description: Boot services
### END INIT INFO
service mysql start \
&& service apache2 start

Answer 1

I've already searched for ideas for my problem but I didn't found anything that I could use.
In almost all cases, you should only run a single process in a single container. Decoupling applications into multiple containers makes it much easier to scale horizontally and reuse containers. If that service depends on another service, make use of container linking.
https://docs.docker.com/engine/userguide/eng-image/dockerfile_best-practices/#/run-only-one-process-per-container

Answer 2

A few pointers that might help you in your path -
Using MySQL and Apache2 in the same container is against
container best practices. Consider dividing the two processes into
separate containers, and connecting them with docker-compose.
Using RUN to start a service will do you no good, since it will run at build time but won't persist when you actually run the container. You should ENTRYPOINT for that, making sure that the script runs on container startup.
If you want to allow yourself connection into the container, you should use docker exec (which executes a command over a running container) over docker run (which tries to launch a new container from the same image)

Answer 3

Thanks for your replies, I had in mind to be able to go in bash mode directly with run...
So you're saying that normally I have to use docker exec to be able to modify my container in contrary to run that should be use to only deploy container ?
I'm going to do it with your advices, thanks ! :D