Overview:

Docker Compose - is a tool for defining and running multi-container Docker applications. With Compose, you use a YAML file to configure your application's services.

Installation:

1. Download the Docker Compose version 1.23.2:

   sudo curl -L "https://github.com/docker/compose/releases/download/1.23.2/docker-compose-$(uname -s)-$(uname -m)" -o /usr/local/bin/docker-compose
   

2. Apply executable permission:

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

3. Test the installation:

   docker-compose --version
   

Basic commands:

1. To create a compose service and startup in the background (before that create docker-compose.yml file):

   docker-compose up -d
   

2. To list the containers created by Docker compose use:

   docker-compose  ps
   

3. To specify compose file use -f flag:

   docker-compose -f [filepath] up -d
   

4. To stop a service:

   docker-compose stop
   

5. To start service:

   docker-compose start
   

6. To restart a service:

   docker-compose restart
   

7. To delete a service:

   docker-compose down
   

Docker Compose file:

1. By default the docker-compose.yml is used to create compose services. You can specify any other file with -f flag
2. There are four types of top level keys in Docker compose file:
   • version
   • services
   • networks
   • volumes
3. Docker compose file format (version) is dependent on which version of Docker you are using
4. Example of docker-compose.yml file which utilizes the Dockerfile. To specify usage of Dockerfile use: build: context::

   version: '3'
   services:
   my-service: # --> Name of the service
    build: # --> Specifies build context
      context: . # --> Path to the Dockerfile (both files in the same directory)
      args:
        - VERSION=v4.1
    ports:
      - "8080:4000"
    environment:
      - ENV=development
   

5. If changes were made into Dockerfile, before starting up a compose service you need to build it again:

   docker-compose build
   

6. To bypass using the cache layers from previous built images use --no-cache flag:

   docker-compose build --no-cache
   

Reference:

1. Compose file version 3 reference
2. Example of installing Drupal with MySQL via Docker Compose
3. How to use volumes in Docker Compose