Using docker image to store data files

Question

I am new to docker and have just started exploring it. What I am trying to achieve is to publish a Docker image, which would just have some configuration files. These files would be shared across multiple projects.

So the image I want to publish is 'my-config-image'.

---

This is how the directory structure is:

/my-config-settings
     /folder1/multiple files
     /folder2/multiple files
     file1.txt
     file2.txt

---

After reading online and going through the docker quick start I have got some understanding.

I decided to use Create a simple base image using scratch. referred from (https://docs.docker.com/engine/userguide/eng-image/baseimages/)

This is how my Dockerfile looks.

FROM scratch
ADD folder1 / folder2 /

This is the command I am using to publish an image.

/my-config-settings/docker build -t my-config-image .
Sending build context to Docker daemon  5.12 kB
Step 1 : FROM scratch
 ---> 
Step 2 : ADD folder1 / folder2 /
 ---> Using cache
 ---> cc9c3f338f51
Successfully built cc9c3f338f51

When I want to check if the image was created locally I am confirming it in this way by executing

docker images


REPOSITORY                                          TAG                 IMAGE ID            CREATED             SIZE
my-config-image                                     latest              cc9c3f338f51        2 minutes ago       39 B

My main query is how can I check if this is working, Also did this add the file1.txt and file2.txt into the image, if not how do I specify to add these files in the image.

Is there a way I can add all the files and directories recursively into the image I am trying to create?

Also how to I access this image, means how can I check if this image actually has all the folders and files. Is there a way to cd into this?

I am okay with suggestions and looking at another docker approach, if what I am trying to do doesn't make sense.

Thank you for reading.

Answer 1

You're trying to address a configuration management problem with an application management approach. For shared configurations, you generally want to take the "centralized location approach". Basic examples of this would be a git repository or an S3 bucket. Both solutions have native document storage and can be appropriately shared between services with fine-grained access control.

A docker image isn't the docker approach to store/share configuration. By having an image, you can basically do two things:
1. Base other images off your initial image
2. Run a container

Given that your image here is just Scratch and files, there are no executables and nothing to run. The hello world example copied a directory with an actual script in it, which is why they ended up with a runnable container.

As a base image, configuration doesn't make sense coming before things like dependencies.

If you really want to use a docker tool for this, you're looking for docker volumes. That can persist a file system and is easy to share around different containers. https://docs.docker.com/engine/userguide/containers/dockervolumes/