CODEWITHSUNDEEP
dockercmddockerfile
jwknz
jwknz

Reputation: 6824

Dockerfile - CMD does not run the shell script

Ok just learning about creating a Dockerfile and my understanding (which is probably wrong) is that the CMD command should be able to run a shell script from within the container once it is placed there.

I am just trying it out with a vanilla apache2 install

Dockerfile

FROM ubuntu:latest

ADD install-apache.sh /Scripts/install-apache.sh
RUN chmod +x /Scripts/install-apache.sh
CMD [/Scripts/install-apache.sh]



RUN echo "Hope this worked!"

I have also tried this:

CMD ["/Scripts/install-apache.sh"]

When I use the RUN command it works (without the [ and ])

So I am a bit lost what the CMD is suppose to do.

I followed the instructions from http://kimh.github.io and read through the docker docs as well.

Question: How am I using the CMD wrong and how should I use it in this scenario?

Upvotes: 2

Views: 4293

Answers (1)

Sebastian
Sebastian

Reputation: 17443

  • RUN is executed while you are building an image. This is usually used to install things or perform modifications in the resulting image.
  • CMD is executed when the container is started. Use this to e.g. start applications.

Also check the docs

The main purpose of a CMD is to provide defaults for an executing container. These defaults can include an executable, or they can omit the executable, in which case you must specify an ENTRYPOINT instruction as well.

Upvotes: 5

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