How to automatically start a service when running

Question

I have a Dockerfile to install MySQL server in a container, which I then start like this:

sudo docker run -t -i 09d18b9a12be /bin/bash

But the MySQL service does not start automatically, I have to manually run (from within the container):

service mysql start

How do I automatically start the MySQL service when I run the docker container?

Answer 1

The following documentation from the Docker website shows how to implement an SSH service in a docker container. It should be easily adaptable for your service:

• https://docs.docker.com/engine/examples/running_ssh_service/

A variation on this question has also been asked here:

• Start sshd automatically with docker container

Answer 2

docker export -o <nameOfContainer>.tar <nameOfContainer>

Might need to prune the existing container using docker prune ...

Import with required modifications:

cat <nameOfContainer>.tar | docker import -c "ENTRYPOINT service mysql start && /bin/bash" - <nameOfContainer>

Run the container for example with always restart option to make sure it will auto resume after host/daemon recycle:

docker run -d -t -i --restart always --name <nameOfContainer> <nameOfContainer> /bin/bash

Side note: In my opinion reasonable is to start only cron service leaving container as clean as possible then just modify crontab or cron.hourly, .daily etc... with corresponding checkup/monitoring scripts. Reason is You rely only on one daemon and in case of changes it is easier with ansible or puppet to redistribute cron scripts instead of track services that start at boot.

Answer 3

I add the following code to /root/.bashrc to run the code only once,

Please commit the container to the image before run this script, otherwise the 'docker_services' file will be created in the images and no service will be run.

if [ ! -e /var/run/docker_services ]; then
    echo "Starting services"
    service mysql start
    service ssh start
    service nginx start
    touch /var/run/docker_services
fi

Answer 4

Here is how I automatically start the MySQL service whenever the docker container runs.

On my case, I need to run not just MySQL but also PHP, Nginx and Memcached

I have the following lines in Dockerfile

RUN echo "daemon off;" >> /etc/nginx/nginx.conf
EXPOSE 80
EXPOSE 3306
CMD service mysql start && service php-fpm start && nginx -g 'daemon off;' && service memcached start && bash

Adding && bash would keep Nginx, MySQL, PHP and Memcached running within the container.

Answer 5

In your Dockerfile, add at the last line

ENTRYPOINT service ssh restart && bash

It works for me

And this is the result:

root@ubuntu:/home/vagrant/docker/add# docker run -i -t ubuntu
 * Restarting OpenBSD Secure Shell server sshd   [ OK ]                                                                      
root@dccc354e422e:~# service ssh status
 * sshd is running

Answer 6

There's another way to do it that I've always found to be more readable.

Say that you want to start rabbitmq and mongodb when you run it then your CMD would look something like this:

CMD /etc/init.d/rabbitmq-server start && \
    /etc/init.d/mongod start

Since you can have only one CMD per Dockerfile the trick is to concatenate all instructions with && and then use \ for each command to start a new line.

If you end up adding to many of those I suggest you put all your commands in a script file and start it like @larry-cai suggested:

CMD /start.sh