In this chapter, we have seen how modern applications are based on microservices. We learned what containers are and their benefits, and how microservices and containers match when we associate a process with specific functionality or a task (microservice) and we run it inside a container. We reviewed container concepts. Then, we talked about images, containers, and the mechanisms that isolate processes from the host. We introduced orchestration and registries as requirements for deploying applications with resilience on cluster environments and the ways in which we can manage images.
We then have learned about Docker's main components and how Docker Client interacts with Docker Engine securely. We introduced the most common Docker objects and the workflow we will use to create, share, and deploy new applications based on containers.
Nowadays, we can use containers on Microsoft Windows, but this all started with Linux. We compared both approaches to understand the similarities and differences between them and the advanced methods used to isolate processes on Windows using Hyper-V.
Finally, we reviewed how to configure Docker Engine using JSON files and environment variables, learned that containers are secure by default, and reviewed the different mechanisms used to accomplish this.
In the next chapter, we will build images using different methods and learn the processes and primitives necessary to create good images.
