Docker Compose YAML file

Before we look at using Docker Compose more, we should have a deeper dive into docker-compose.yml files as these are the heart of Docker Compose.

YAML is a recursive acronym that stands for YAML Ain't Markup Language. It is used by a lot of different applications for both configuration and also for defining data in a human-readable structured data format. The indentation you see in the examples is very important as it helps to define the structure of the data.

Moby counter application

The docker-compose.yml file we used to launch our multi-container application is split into three separate sections.

The first section simply specifies which version of the Docker Compose definition language we are...