Containers — 101

The post provides a quick overview on Containers. It covers definition, how it benefits the software delivery, and a short demo to illustrate how it works.

Containers: Single Deployable Unit

Definition

Docker has revolutionized the container technology and made itself a de facto standard to build and share containerized apps. It defines the container like this —

A container is a standard unit of software that packages up code and all its dependencies so the application runs quickly and reliably from one computing environment to another.

Lets try to decrypt the definition and understand all the bits of it.

What do we mean by ‘all its dependencies’?

Let’s say you are building a web application based on Java and Spring Boot. If you need to deploy the application in an integrated environment like production or test, you need to consider multiple components —

• source code — contains the core application
• 3rd party libraries — Even the basic web application with spring-boot will have 10–20 external libraries including spring-boot framework components, logging utility, JSON parser, and many others. Here is the list of dependency libraries from…