Understanding docker-compose and images

Before we explore docker-compose and how it compiles our images, we need to understand the concept of orchestration and why we need it. Container orchestration is an automated approach to launching containers and related services. In context, when we have a containerized application, we might end up with several containers between our application that has been containerized and third-party applications that we are using as containers.

In the context of our microservices application where we have several individual services, each one is containerized. We might also end up using a containerized cache server, and other supporting services such as email and logging applications. We now need a way to organize our list of containers and launch them in a particular order, such that the supporting applications are available before the dependent service containers are launched.

This requirement introduces a considerable amount of complexity and...