Introduction to Docker: a Beginner’s Guide

Docker is one of the most popular tools for application containerization. Docker enables efficiency and reduces operational overheads so that any developer, in any dev environment, can build stable and reliable applications.

Let’s take a look at Docker, starting with application development before Docker.

(This is part of our Docker Guide. Use the right-hand menu to navigate.)

App development today

One common challenge for DevOps teams is managing an application’s dependencies and technology stack across various cloud and development environments. As part of their routine tasks, they must keep the application operational and stable—regardless of the underlying platform that it runs on.

Development teams, on the other hand, focus on releasing new features and updates. Unfortunately, these often compromise the application’s stability by deploying codes that introduce environment-dependent bugs.

To avoid this inefficiency, organizations are increasingly adopting a containerized framework that allows designing a stable framework without adding:

• Complexities
• Security vulnerabilities
• Operational loose ends

Put simply, containerization is the process of packaging an application’s code—with dependencies, libraries, and configuration files that the application needs to launch and operate efficiently—into a standalone executable unit.

Initially, containers didn’t gain much prominence, mostly due to usability issues. However, since Docker entered the scene by addressing these challenges, containers have become practically mainstream.

What is Docker?

Docker is a Linux-based, open-source containerization platform that developers use to build, run, and package applications for deployment using containers. Unlike virtual machines, Docker containers offer:

• OS-level abstraction with optimum resource utilization
• Interoperability
• Efficient build and test
• Faster application execution

Fundamentally, Docker containers modularize an application’s functionality into multiple components that allow deploying, testing, or scaling them independently when needed.

Take, for instance, a Docker containerized database of an application. With such a framework, you can scale or maintain the database independently from other modules/components of the application without impacting the workloads of other critical systems.