Installing Docker Compose on Debian 9

Docker Compose is a tool for defining and running multi-container Docker applications. Services are configured in a YAML file, letting you spin up the entire environment with a single command.

Key features:

• multiple isolated environments on a single host;
• volume data is preserved when containers are recreated;
• only changed containers are recreated;
• variables can be passed between environments.

Before installing Docker Compose, make sure Docker is already installed — see Installing Docker on Debian 9.

Installation

Download Docker Compose from the GitHub repository. Check the latest release and update the version number in the command if needed:

sudo curl -L https://github.com/docker/compose/releases/download/1.25.5/docker-compose-`uname -s`-`uname -m` -o /usr/local/bin/docker-compose

Set the execute permission:

sudo chmod +x /usr/local/bin/docker-compose

Verify the installation:

docker-compose --version

Expected output:

docker-compose version 1.25.5, build 8a1c60f6

Running a container with Docker Compose

Create a directory for the test project and navigate into it:

mkdir hello-world
cd hello-world

Create a docker-compose.yml file:

nano docker-compose.yml

Add the following content and save the file:

my-test:
 image: hello-world

The first line defines part of the container name, the second specifies the image. When docker-compose up runs, Docker looks for the image locally first, then pulls it from Docker Hub if not found.

Check the list of local images:

docker images

If no images are present, only column headers will appear:

REPOSITORY          TAG                 IMAGE ID            CREATED             SIZE

Start the container:

docker-compose up

Docker will pull the image, create the container, and run it:

Creating hello-world_my-test_1 ... done
Attaching to hello-world_my-test_1
my-test_1  | 
my-test_1  | Hello from Docker!
my-test_1  | This message shows that your installation appears to be working correctly.
...
hello-world_my-test_1 exited with code 0

The container stops once the program finishes. It won't appear in the list of active processes:

docker ps

To view all containers including stopped ones, use the -a flag:

docker ps -a

Example output:

CONTAINER ID   IMAGE         COMMAND    CREATED         STATUS                     NAMES
4e8158d490ac   hello-world   "/hello"   7 minutes ago   Exited (0) 7 minutes ago   hello-world_my-test_1