Introduction to Containerization

Objectives

In this chapter, you will complete a typical workflow to build an application into a container image. This process is called containerization and the resulting application is called a containerized application.

You will use Docker to containerize the application (i.e. create the container image) and the steps that will be followed are not specific to the use of Kubernetes. In fact, you will not use Kubernetes in this chapter. However, the containerized application you create will be deployed to Kubernetes in the following chapters.

Note: Kubernetes has started the process of withdrawing support for Docker as its container runtime. However, containerized applications created by Docker are still 100% supported in Kubernetes. This is because Kubernetes and Docker both work with container images based on the standards set by the Open Container Initiative (OCI).

You can skip this chapter if you are already familiar with Docker and the procedure for creating containerized applications. We have a premade containerized application available on Docker Hub for you to use in the practice sessions that will follow.

Still here?

Great. The workflow you will follow is shown below. Step 1 will be touched upon briefly, but the main focus will be on steps 2 and 3. Future chapters will cover step 4.