Correct way to deploy WAR files in docker image

Question

What is the docker way to deploy java projects in a docker container?

Do I copy the war into webapps:

FROM jetty:9.2.10
MAINTAINER Me \"me@me.com\"
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Answer 1

I wonder how you're using your images. Adding a 20MB file while building an image should almost be instant. Mayb you somehow building images during deployment, like AWS does when you give it a Dockerfile.

In any case, I think it depends on how you're deploying. If you're moving the images around yourself, I don't see a lot of difference between ADDing a .war file and an exploded WAR directory. I would say do what's convenient for you. However, if you sometimes run the app from Docker and sometimes from a .war (which might miss some of the point of Docker), you might as well use the .war all the time.

If you're deploying to something like AWS Elastic Beanstalk (something that pulls the image from a repository), which wants either a Dockerfile or a Dockerrun.aws.json file, then separating the image from what you actually deploy makes some sense (or it has made sense to me so far). This allows the container to stay the same, while updating your app can be just copying a .jar/.war file to the right location (which also might miss part of the point of Docker ;).

What I've been doing is creating a base image on Docker Hub and then using the Dockerrun.aws.json file to map in my app. That way, AWS does not need to build my image, just pull it. That's much faster and less costly ($). But it does separate my app from the image, which might complicate deployment in some circumstances. However, because my image is so stable, I generally just bundle a .jar file, a Dockerrun.aws.json file and a shell script into a .zip and upload it to AWS. Pretty easy I think.

My Dockerfile is pretty simple and really all I need for my Spring Boot app:

FROM java:8
VOLUME /tmp
VOLUME /app
EXPOSE 8080
ENTRYPOINT ["sh","/app/app.sh"]

You could do something similar and use the -v option, etc., to map volumes to your app, it's environment settings, etc. BTW, this image is available on Docker Hub.