How Does Docker Containerization Work?

Docker transformed how we build, ship, and run applications by introducing lightweight containerization to the mainstream. After implementing Docker in production environments for over a decade, I’ve seen firsthand how it solves the classic “it works on my machine” problem while providing unprecedented deployment flexibility. This deep dive explains exactly how Docker achieves application isolation without the overhead of virtual machines.

Understanding Containerization

Containerization packages applications with their complete runtime environment—code, dependencies, libraries, and configuration—into a single executable unit. Unlike virtual machines that virtualize hardware, containers virtualize the operating system, sharing the host kernel while maintaining process isolation.