The docker-compose tool allows us to define a multi-container Docker application and run it using a single command, docker-compose up.
docker-compose works by reading a docker-compose.yml file that contains specific instructions that not only describe the containers in the application, but also their individual dependencies. Let's examine each section of the docker-compose.yml file for the multi-container igweb application.
In the first line of the file, we indicate that we will be using version 2 of the Docker Compose configuration file format:
We declare the application's services inside the services section. Each service (shown in bold) is given a name to indicate its role in the multi-container application: ...