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How to Put Docker Compose Files Under Git Version Control

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Consider an application that consists of many individual projects. The frontend and backend are separate. The backend splits into many parts, like API and services. And the docker-compose.yml file lives inside the root directory of all these projects.

my-project
├─ api
├─ service-one
├─ service-two
├─ client
├─ docker-compose.yml

Each individual part — api, client, and others — is a Git repository. The root directory itself is not, so changes to the Compose file are not tracked.

How do you version control your docker-compose.yml file in such layout?

The short answer is to set up a Git repository for Compose files and use a symbolic link.

ln -s /path/to/repository/app-compose.yml /path/to/app/docker-compose.yml

Continue reading for more details.

Step 1 — Creating a Repository for Compose Files

Set up a Git repository where you will keep all your Compose files for each application you work on.

cd ~/Projects
mkdir docker-compose-files
cd docker-compose-files
git init

This will create a new directory in ~/Projects/docker-compose-files and initialize a new Git repository.

You are ready to track changes to your Compose files.

Step 2 — Adding Compose File to Version Control

Move your current project’s Compose file to the newly created Git repository.

mv ~/Projects/my-project/docker-compose.yml ./my-project-compose.yml
git add .
git commit -m "Add my-project-compose.yml"

The docker-compose-files repository you just created will now track changes to your Compose files.

But, now you need to get the version-controlled Compose file back into your project.

Step 3 — Setting up Symbolic Link

Now create a reference of the version-controlled Compose file to your application directory.

You need to first specify a path to the Compose file in your version control repository. Then, specify a path to your application’s root directory, where you would like to keep the Compose file.

ln -s $PWD/my-project-compose.yml ~/Projects/my-project/docker-compose.yml

This command creates a link from your application’s root to the Compose file under version control.

You can use $PWD environment variable to reference your current working directory.

The -s argument is what creates a symbolic link, omitting it would create a hard link.

Result

Projects folder structure should look something like this.

Projects
├─ docker-compose-files
│  ├─ my-project-compose.yml
├─ my-project
│  ├─ api
│  ├─ service-one
│  ├─ service-two
│  ├─ client
│  ├─ docker-compose.yml

Making changes to my-project-compose.yml or docker-compose.yml will reflect in the other file.

The docker-compose-files repository will track any changes you make to these files.

While working on your application, you can edit the docker-compose.yml file. But, after doing so, you must commit your changes of my-project-compose.yml file inside the docker-compose-files repository.

When you start a new project, create a Compose file in docker-compose-files repository. After that, create a link to your project’s root directory, and you’re done.