defining multiple services on Dockerfile with single CMD

Question

Say I have the commands:

rails server

and

bundle exec something:default

I understand my Dockerfile can only have 1 CMD line so is it ok to do:

CMD ["sh", "-c", "rail server && bundle exec something:default"]

As it's just those 2 commands, I don't want to COPY a script.sh then use that (hoping for a simple 1 line way).

Is there a best practice I should be aware of when running 2 services in one container?

Answer 1

It is best practice to run a single service in each container, but it is not always practical. I run CMD ["sh", "-c", "/usr/sbin/crond && php-fpm"] so I can use the laravel scheduler. So in answer to the question, yes the above does work.

Answer 2

You can create a bash script

#!/bin/bash
rail server
bundle exec something:default

then add a COPY to your Dockerfile

COPY mycmd.sh /app

/app is your destination

and finally execute your script in a CMD step

CMD ["mycmd.sh"]