How to escape CMD in Dockerfile

Question

I've tried to start a server inside docker via the following syntax permutations:

1. CMD [ "forever", "start", "server/server.js" ]
2. CMD [ "forever", "start", "server\/server.js" ]
3. CMD forever start server/server.js

But each of them has failed.

The first two ran as "forever start server" ... notice the missing /server.js piece.

The last one ran as "/bin/sh -c 'forever "

So what is the correct syntax to place forever start server/server.js inside a Dockerfile to run it as a detached container?

Answer 1

I've just run into the same issue with starting a Java application inside the docker container when running it.

From the docker reference you have three opportunities:

CMD ["executable","param1","param2"]
CMD ["param1","param2"]
CMD command param1 param2

Have a look here: Docker CMD

I'm not familiar with JavaScript, but assuming that the application you want to start is a Java application:

CMD ["/some path/jre64/bin/java", "server.jar", "start", "forever", ...]

And as the others in your comments say, you could also add the script via docker ADD or COPY in your Dockerfile and start it with docker RUN.

Yet another solution would be to run the docker container and mount a directory with the desired script via docker run .. -v HOSTDIR:CONTAINERDIR inside the container and trigger that script with docker exec.

Have a read here: Docker Filemounting + Docker Exec