Containerization

After virtualization solved the problem of hardware inefficiency, the industry was still left with a major challenge: application portability and environment consistency. Virtual machines made servers easier to provision, but application were still tightly coupled to operating systems and manual configuration.

Containerization emerged as the next evolution – shifting the abstraction from hardware to the application runtime itself.

The Problem Virtual Machine Couldn't Solve

Even with virtual machines:

• Each VM had its own OS
• Environment setup was manual
• Dev, staging, and prod drifted over time
• Deployments were slow and risky

Teams still heard:

“It works on my machine:”

The core issue was that the unit of deployment was still the server, not the application.

What is Containerization?

Containerization packages:

• Application code
• Runtime
• System libraries
• Dependencies

into a single, self-contained unit called a container.

A container:

• Runs as a isolated process
• Shares the host OS kernel
• Behaves the same across environments

This made the application the unit of deployment.

Containers vs Virtual Machines

Containers are not replacements for VMs – they are a higher-level abstraction built on top of them.