Docker: Combine multiple images

No, you can only inherit from one image.

You probably don't want Java and MySQL in the same image as it's more idiomatic to have a single component in a container i.e. create a separate MySQL container and link it to the Java container rather than put both into the same container.

However, if you really must have them in the same image, write a Dockerfile with Java as the base image (FROM statement) and install MySQL in the Dockerfile. You should be able to largely copy the statements from the official MySQL Dockerfile.

Docker doesn't directly support this, but you can use DockerMake (full disclosure: I wrote it) to manage this sort of "inheritance". It uses a YAML file to set up the individual pieces of the image, then drives the build by generating the appropriate Dockerfiles.

Here's how you would build this slightly more complicated example:

                                     --> genericA --
                                    /                \
      debian:jessie -->  customBase                   ---> specificAB
                                    \                /
                                      --> genericB --

You would use this DockerMake.yml file:

specificAB:
  requires:
    - genericA
    - genericB

genericA:
  requires:
     - customBase
  build_directory: [some local directory]
  build: |
    #Dockerfile commands go here, such as
    ADD installA.sh
    RUN ./installA.sh

genericB:
  requires:
    - customBase
  build: |
    #Here are some other commands you could run
    RUN apt-get install -y genericB
    ENV PATH=$PATH:something

customBase:
  FROM: debian:jessie
  build: |
    RUN apt-get update && apt-get install -y buildessentials

After installing the docker-make CLI tool (pip install dockermake), you can then build the specificAB image just by running

docker-make specificAB

If you do docker commit, it is not handy to see what commands were used in order to build your container, you have to issue a docker history image

If you have a Dockerfile, just look at it and you see how it was built and what it contains.

Docker commit is 'by hand', so prone to errors, docker build using a Dockerfile that works is much better.